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JavaScript | 2008-03-03 | 30.7 KB | 873 lines

/*
 * jQuery Form Plugin
 * version: 2.02 (12/16/2007)
 * @requires jQuery v1.1 or later
 *
 * Examples at: http://malsup.com/jquery/form/
 * Dual licensed under the MIT and GPL licenses:
 *   http://www.opensource.org/licenses/mit-license.php
 *   http://www.gnu.org/licenses/gpl.html
 *
 * Revision: $Id$
 */
 (function($) {
/**
 * ajaxSubmit() provides a mechanism for submitting an HTML form using AJAX.
 *
 * ajaxSubmit accepts a single argument which can be either a success callback function
 * or an options Object.  If a function is provided it will be invoked upon successful
 * completion of the submit and will be passed the response from the server.
 * If an options Object is provided, the following attributes are supported:
 *
 *  target:   Identifies the element(s) in the page to be updated with the server response.
 *            This value may be specified as a jQuery selection string, a jQuery object,
 *            or a DOM element.
 *            default value: null
 *
 *  url:      URL to which the form data will be submitted.
 *            default value: value of form's 'action' attribute
 *
 *  type:     The method in which the form data should be submitted, 'GET' or 'POST'.
 *            default value: value of form's 'method' attribute (or 'GET' if none found)
 *
 *  data:     Additional data to add to the request, specified as key/value pairs (see $.ajax).
 *
 *  beforeSubmit:  Callback method to be invoked before the form is submitted.
 *            default value: null
 *
 *  success:  Callback method to be invoked after the form has been successfully submitted
 *            and the response has been returned from the server
 *            default value: null
 *
 *  dataType: Expected dataType of the response.  One of: null, 'xml', 'script', or 'json'
 *            default value: null
 *
 *  semantic: Boolean flag indicating whether data must be submitted in semantic order (slower).
 *            default value: false
 *
 *  resetForm: Boolean flag indicating whether the form should be reset if the submit is successful
 *
 *  clearForm: Boolean flag indicating whether the form should be cleared if the submit is successful
 *
 *
 * The 'beforeSubmit' callback can be provided as a hook for running pre-submit logic or for
 * validating the form data.  If the 'beforeSubmit' callback returns false then the form will
 * not be submitted. The 'beforeSubmit' callback is invoked with three arguments: the form data
 * in array format, the jQuery object, and the options object passed into ajaxSubmit.
 * The form data array takes the following form:
 *
 *     [ { name: 'username', value: 'jresig' }, { name: 'password', value: 'secret' } ]
 *
 * If a 'success' callback method is provided it is invoked after the response has been returned
 * from the server.  It is passed the responseText or responseXML value (depending on dataType).
 * See jQuery.ajax for further details.
 *
 *
 * The dataType option provides a means for specifying how the server response should be handled.
 * This maps directly to the jQuery.httpData method.  The following values are supported:
 *
 *      'xml':    if dataType == 'xml' the server response is treated as XML and the 'success'
 *                   callback method, if specified, will be passed the responseXML value
 *      'json':   if dataType == 'json' the server response will be evaluted and passed to
 *                   the 'success' callback, if specified
 *      'script': if dataType == 'script' the server response is evaluated in the global context
 *
 *
 * Note that it does not make sense to use both the 'target' and 'dataType' options.  If both
 * are provided the target will be ignored.
 *
 * The semantic argument can be used to force form serialization in semantic order.
 * This is normally true anyway, unless the form contains input elements of type='image'.
 * If your form must be submitted with name/value pairs in semantic order and your form
 * contains an input of type='image" then pass true for this arg, otherwise pass false
 * (or nothing) to avoid the overhead for this logic.
 *
 *
 * When used on its own, ajaxSubmit() is typically bound to a form's submit event like this:
 *
 * $("#form-id").submit(function() {
 *     $(this).ajaxSubmit(options);
 *     return false; // cancel conventional submit
 * });
 *
 * When using ajaxForm(), however, this is done for you.
 *
 * @example
 * $('#myForm').ajaxSubmit(function(data) {
 *     alert('Form submit succeeded! Server returned: ' + data);
 * });
 * @desc Submit form and alert server response
 *
 *
 * @example
 * var options = {
 *     target: '#myTargetDiv'
 * };
 * $('#myForm').ajaxSubmit(options);
 * @desc Submit form and update page element with server response
 *
 *
 * @example
 * var options = {
 *     success: function(responseText) {
 *         alert(responseText);
 *     }
 * };
 * $('#myForm').ajaxSubmit(options);
 * @desc Submit form and alert the server response
 *
 *
 * @example
 * var options = {
 *     beforeSubmit: function(formArray, jqForm) {
 *         if (formArray.length == 0) {
 *             alert('Please enter data.');
 *             return false;
 *         }
 *     }
 * };
 * $('#myForm').ajaxSubmit(options);
 * @desc Pre-submit validation which aborts the submit operation if form data is empty
 *
 *
 * @example
 * var options = {
 *     url: myJsonUrl.php,
 *     dataType: 'json',
 *     success: function(data) {
 *        // 'data' is an object representing the the evaluated json data
 *     }
 * };
 * $('#myForm').ajaxSubmit(options);
 * @desc json data returned and evaluated
 *
 *
 * @example
 * var options = {
 *     url: myXmlUrl.php,
 *     dataType: 'xml',
 *     success: function(responseXML) {
 *        // responseXML is XML document object
 *        var data = $('myElement', responseXML).text();
 *     }
 * };
 * $('#myForm').ajaxSubmit(options);
 * @desc XML data returned from server
 *
 *
 * @example
 * var options = {
 *     resetForm: true
 * };
 * $('#myForm').ajaxSubmit(options);
 * @desc submit form and reset it if successful
 *
 * @example
 * $('#myForm).submit(function() {
 *    $(this).ajaxSubmit();
 *    return false;
 * });
 * @desc Bind form's submit event to use ajaxSubmit
 *
 *
 * @name ajaxSubmit
 * @type jQuery
 * @param options  object literal containing options which control the form submission process
 * @cat Plugins/Form
 * @return jQuery
 */
$.fn.ajaxSubmit = function(options) {
    if (typeof options == 'function')
        options = { success: options };

    options = $.extend({
        url:  this.attr('action') || window.location.toString(),
        type: this.attr('method') || 'GET'
    }, options || {});

    // hook for manipulating the form data before it is extracted;
    // convenient for use with rich editors like tinyMCE or FCKEditor
    var veto = {};
    $.event.trigger('form.pre.serialize', [this, options, veto]);
    if (veto.veto) return this;

    var a = this.formToArray(options.semantic);
    if (options.data) {
        for (var n in options.data)
            a.push( { name: n, value: options.data[n] } );
    }

    // give pre-submit callback an opportunity to abort the submit
    if (options.beforeSubmit && options.beforeSubmit(a, this, options) === false) return this;

    // fire vetoable 'validate' event
    $.event.trigger('form.submit.validate', [a, this, options, veto]);
    if (veto.veto) return this;

    var q = $.param(a);//.replace(/%20/g,'+');

    if (options.type.toUpperCase() == 'GET') {
        options.url += (options.url.indexOf('?') >= 0 ? '&' : '?') + q;
        options.data = null;  // data is null for 'get'
    }
    else
        options.data = q; // data is the query string for 'post'

    var $form = this, callbacks = [];
    if (options.resetForm) callbacks.push(function() { $form.resetForm(); });
    if (options.clearForm) callbacks.push(function() { $form.clearForm(); });

    // perform a load on the target only if dataType is not provided
    if (!options.dataType && options.target) {
        var oldSuccess = options.success || function(){};
        callbacks.push(function(data) {
            if (this.evalScripts)
                $(options.target).attr("innerHTML", data).evalScripts().each(oldSuccess, arguments);
            else // jQuery v1.1.4
                $(options.target).html(data).each(oldSuccess, arguments);
        });
    }
    else if (options.success)
        callbacks.push(options.success);

    options.success = function(data, status) {
        for (var i=0, max=callbacks.length; i < max; i++)
            callbacks[i](data, status, $form);
    };

    // are there files to upload?
    var files = $('input:file', this).fieldValue();
    var found = false;
    for (var j=0; j < files.length; j++)
        if (files[j])
            found = true;

    // options.iframe allows user to force iframe mode
   if (options.iframe || found) {
       // hack to fix Safari hang (thanks to Tim Molendijk for this)
       // see:  http://groups.google.com/group/jquery-dev/browse_thread/thread/36395b7ab510dd5d
       if ($.browser.safari && options.closeKeepAlive)
           $.get(options.closeKeepAlive, fileUpload);
       else
           fileUpload();
       }
   else
       $.ajax(options);

    // fire 'notify' event
    $.event.trigger('form.submit.notify', [this, options]);
    return this;


    // private function for handling file uploads (hat tip to YAHOO!)
    function fileUpload() {
        var form = $form[0];
        var opts = $.extend({}, $.ajaxSettings, options);

        var id = 'jqFormIO' + $.fn.ajaxSubmit.counter++;
        var $io = $('<iframe id="' + id + '" name="' + id + '" />');
        var io = $io[0];
        var op8 = $.browser.opera && window.opera.version() < 9;
        if ($.browser.msie || op8) io.src = 'javascript:false;document.write("");';
        $io.css({ position: 'absolute', top: '-1000px', left: '-1000px' });

        var xhr = { // mock object
            responseText: null,
            responseXML: null,
            status: 0,
            statusText: 'n/a',
            getAllResponseHeaders: function() {},
            getResponseHeader: function() {},
            setRequestHeader: function() {}
        };

        var g = opts.global;
        // trigger ajax global events so that activity/block indicators work like normal
        if (g && ! $.active++) $.event.trigger("ajaxStart");
        if (g) $.event.trigger("ajaxSend", [xhr, opts]);

        var cbInvoked = 0;
        var timedOut = 0;

        // take a breath so that pending repaints get some cpu time before the upload starts
        setTimeout(function() {
            // make sure form attrs are set
            var encAttr = form.encoding ? 'encoding' : 'enctype';
            var t = $form.attr('target');
            $form.attr({
                target:   id,
                method:  'POST',
                action:   opts.url
            });
            form[encAttr] = 'multipart/form-data';

            // support timout
            if (opts.timeout)
                setTimeout(function() { timedOut = true; cb(); }, opts.timeout);

            // add iframe to doc and submit the form
            $io.appendTo('body');
            io.attachEvent ? io.attachEvent('onload', cb) : io.addEventListener('load', cb, false);
            form.submit();
            $form.attr('target', t); // reset target
        }, 10);

        function cb() {
            if (cbInvoked++) return;

            io.detachEvent ? io.detachEvent('onload', cb) : io.removeEventListener('load', cb, false);

            var ok = true;
            try {
                if (timedOut) throw 'timeout';
                // extract the server response from the iframe
                var data, doc;
                doc = io.contentWindow ? io.contentWindow.document : io.contentDocument ? io.contentDocument : io.document;
                xhr.responseText = doc.body ? doc.body.innerHTML : null;
                xhr.responseXML = doc.XMLDocument ? doc.XMLDocument : doc;

                if (opts.dataType == 'json' || opts.dataType == 'script') {
                    var ta = doc.getElementsByTagName('textarea')[0];
                    data = ta ? ta.value : xhr.responseText;
                    if (opts.dataType == 'json')
                        eval("data = " + data);
                    else
                        $.globalEval(data);
                }
                else if (opts.dataType == 'xml') {
                    data = xhr.responseXML;
                    if (!data && xhr.responseText != null)
                        data = toXml(xhr.responseText);
                }
                else {
                    data = xhr.responseText;
                }
            }
            catch(e){
                ok = false;
                $.handleError(opts, xhr, 'error', e);
            }

            // ordering of these callbacks/triggers is odd, but that's how $.ajax does it
            if (ok) {
                opts.success(data, 'success');
                if (g) $.event.trigger("ajaxSuccess", [xhr, opts]);
            }
            if (g) $.event.trigger("ajaxComplete", [xhr, opts]);
            if (g && ! --$.active) $.event.trigger("ajaxStop");
            if (opts.complete) opts.complete(xhr, ok ? 'success' : 'error');

            // clean up
            setTimeout(function() {
                $io.remove();
                xhr.responseXML = null;
            }, 100);
        };

        function toXml(s, doc) {
            if (window.ActiveXObject) {
                doc = new ActiveXObject('Microsoft.XMLDOM');
                doc.async = 'false';
                doc.loadXML(s);
            }
            else
                doc = (new DOMParser()).parseFromString(s, 'text/xml');
            return (doc && doc.documentElement && doc.documentElement.tagName != 'parsererror') ? doc : null;
        };
    };
};
$.fn.ajaxSubmit.counter = 0; // used to create unique iframe ids

/**
 * ajaxForm() provides a mechanism for fully automating form submission.
 *
 * The advantages of using this method instead of ajaxSubmit() are:
 *
 * 1: This method will include coordinates for <input type="image" /> elements (if the element
 *    is used to submit the form).
 * 2. This method will include the submit element's name/value data (for the element that was
 *    used to submit the form).
 * 3. This method binds the submit() method to the form for you.
 *
 * Note that for accurate x/y coordinates of image submit elements in all browsers
 * you need to also use the "dimensions" plugin (this method will auto-detect its presence).
 *
 * The options argument for ajaxForm works exactly as it does for ajaxSubmit.  ajaxForm merely
 * passes the options argument along after properly binding events for submit elements and
 * the form itself.  See ajaxSubmit for a full description of the options argument.
 *
 *
 * @example
 * var options = {
 *     target: '#myTargetDiv'
 * };
 * $('#myForm').ajaxSForm(options);
 * @desc Bind form's submit event so that 'myTargetDiv' is updated with the server response
 *       when the form is submitted.
 *
 *
 * @example
 * var options = {
 *     success: function(responseText) {
 *         alert(responseText);
 *     }
 * };
 * $('#myForm').ajaxSubmit(options);
 * @desc Bind form's submit event so that server response is alerted after the form is submitted.
 *
 *
 * @example
 * var options = {
 *     beforeSubmit: function(formArray, jqForm) {
 *         if (formArray.length == 0) {
 *             alert('Please enter data.');
 *             return false;
 *         }
 *     }
 * };
 * $('#myForm').ajaxSubmit(options);
 * @desc Bind form's submit event so that pre-submit callback is invoked before the form
 *       is submitted.
 *
 *
 * @name   ajaxForm
 * @param  options  object literal containing options which control the form submission process
 * @return jQuery
 * @cat    Plugins/Form
 * @type   jQuery
 */
$.fn.ajaxForm = function(options) {
    return this.ajaxFormUnbind().submit(submitHandler).each(function() {
        // store options in hash
        this.formPluginId = $.fn.ajaxForm.counter++;
        $.fn.ajaxForm.optionHash[this.formPluginId] = options;
        $(":submit,input:image", this).click(clickHandler);
    });
};

$.fn.ajaxForm.counter = 1;
$.fn.ajaxForm.optionHash = {};

function clickHandler(e) {
    var $form = this.form;
    $form.clk = this;
    if (this.type == 'image') {
        if (e.offsetX != undefined) {
            $form.clk_x = e.offsetX;
            $form.clk_y = e.offsetY;
        } else if (typeof $.fn.offset == 'function') { // try to use dimensions plugin
            var offset = $(this).offset();
            $form.clk_x = e.pageX - offset.left;
            $form.clk_y = e.pageY - offset.top;
        } else {
            $form.clk_x = e.pageX - this.offsetLeft;
            $form.clk_y = e.pageY - this.offsetTop;
        }
    }
    // clear form vars
    setTimeout(function() { $form.clk = $form.clk_x = $form.clk_y = null; }, 10);
};

function submitHandler() {
    // retrieve options from hash
    var id = this.formPluginId;
    var options = $.fn.ajaxForm.optionHash[id];
    $(this).ajaxSubmit(options);
    return false;
};

/**
 * ajaxFormUnbind unbinds the event handlers that were bound by ajaxForm
 *
 * @name   ajaxFormUnbind
 * @return jQuery
 * @cat    Plugins/Form
 * @type   jQuery
 */
$.fn.ajaxFormUnbind = function() {
    this.unbind('submit', submitHandler);
    return this.each(function() {
        $(":submit,input:image", this).unbind('click', clickHandler);
    });

};

/**
 * formToArray() gathers form element data into an array of objects that can
 * be passed to any of the following ajax functions: $.get, $.post, or load.
 * Each object in the array has both a 'name' and 'value' property.  An example of
 * an array for a simple login form might be:
 *
 * [ { name: 'username', value: 'jresig' }, { name: 'password', value: 'secret' } ]
 *
 * It is this array that is passed to pre-submit callback functions provided to the
 * ajaxSubmit() and ajaxForm() methods.
 *
 * The semantic argument can be used to force form serialization in semantic order.
 * This is normally true anyway, unless the form contains input elements of type='image'.
 * If your form must be submitted with name/value pairs in semantic order and your form
 * contains an input of type='image" then pass true for this arg, otherwise pass false
 * (or nothing) to avoid the overhead for this logic.
 *
 * @example var data = $("#myForm").formToArray();
 * $.post( "myscript.cgi", data );
 * @desc Collect all the data from a form and submit it to the server.
 *
 * @name formToArray
 * @param semantic true if serialization must maintain strict semantic ordering of elements (slower)
 * @type Array<Object>
 * @cat Plugins/Form
 */
$.fn.formToArray = function(semantic) {
    var a = [];
    if (this.length == 0) return a;

    var form = this[0];
    var els = semantic ? form.getElementsByTagName('*') : form.elements;
    if (!els) return a;
    for(var i=0, max=els.length; i < max; i++) {
        var el = els[i];
        var n = el.name;
        if (!n) continue;

        if (semantic && form.clk && el.type == "image") {
            // handle image inputs on the fly when semantic == true
            if(!el.disabled && form.clk == el)
                a.push({name: n+'.x', value: form.clk_x}, {name: n+'.y', value: form.clk_y});
            continue;
        }

        var v = $.fieldValue(el, true);
        if (v && v.constructor == Array) {
            for(var j=0, jmax=v.length; j < jmax; j++)
                a.push({name: n, value: v[j]});
        }
        else if (v !== null && typeof v != 'undefined')
            a.push({name: n, value: v});
    }

    if (!semantic && form.clk) {
        // input type=='image' are not found in elements array! handle them here
        var inputs = form.getElementsByTagName("input");
        for(var i=0, max=inputs.length; i < max; i++) {
            var input = inputs[i];
            var n = input.name;
            if(n && !input.disabled && input.type == "image" && form.clk == input)
                a.push({name: n+'.x', value: form.clk_x}, {name: n+'.y', value: form.clk_y});
        }
    }
    return a;
};


/**
 * Serializes form data into a 'submittable' string. This method will return a string
 * in the format: name1=value1&name2=value2
 *
 * The semantic argument can be used to force form serialization in semantic order.
 * If your form must be submitted with name/value pairs in semantic order then pass
 * true for this arg, otherwise pass false (or nothing) to avoid the overhead for
 * this logic (which can be significant for very large forms).
 *
 * @example var data = $("#myForm").formSerialize();
 * $.ajax('POST', "myscript.cgi", data);
 * @desc Collect all the data from a form into a single string
 *
 * @name formSerialize
 * @param semantic true if serialization must maintain strict semantic ordering of elements (slower)
 * @type String
 * @cat Plugins/Form
 */
$.fn.formSerialize = function(semantic) {
    //hand off to jQuery.param for proper encoding
    return $.param(this.formToArray(semantic));
};


/**
 * Serializes all field elements in the jQuery object into a query string.
 * This method will return a string in the format: name1=value1&name2=value2
 *
 * The successful argument controls whether or not serialization is limited to
 * 'successful' controls (per http://www.w3.org/TR/html4/interact/forms.html#successful-controls).
 * The default value of the successful argument is true.
 *
 * @example var data = $("input").formSerialize();
 * @desc Collect the data from all successful input elements into a query string
 *
 * @example var data = $(":radio").formSerialize();
 * @desc Collect the data from all successful radio input elements into a query string
 *
 * @example var data = $("#myForm :checkbox").formSerialize();
 * @desc Collect the data from all successful checkbox input elements in myForm into a query string
 *
 * @example var data = $("#myForm :checkbox").formSerialize(false);
 * @desc Collect the data from all checkbox elements in myForm (even the unchecked ones) into a query string
 *
 * @example var data = $(":input").formSerialize();
 * @desc Collect the data from all successful input, select, textarea and button elements into a query string
 *
 * @name fieldSerialize
 * @param successful true if only successful controls should be serialized (default is true)
 * @type String
 * @cat Plugins/Form
 */
$.fn.fieldSerialize = function(successful) {
    var a = [];
    this.each(function() {
        var n = this.name;
        if (!n) return;
        var v = $.fieldValue(this, successful);
        if (v && v.constructor == Array) {
            for (var i=0,max=v.length; i < max; i++)
                a.push({name: n, value: v[i]});
        }
        else if (v !== null && typeof v != 'undefined')
            a.push({name: this.name, value: v});
    });
    //hand off to jQuery.param for proper encoding
    return $.param(a);
};


/**
 * Returns the value(s) of the element in the matched set.  For example, consider the following form:
 *
 *  <form><fieldset>
 *      <input name="A" type="text" />
 *      <input name="A" type="text" />
 *      <input name="B" type="checkbox" value="B1" />
 *      <input name="B" type="checkbox" value="B2"/>
 *      <input name="C" type="radio" value="C1" />
 *      <input name="C" type="radio" value="C2" />
 *  </fieldset></form>
 *
 *  var v = $(':text').fieldValue();
 *  // if no values are entered into the text inputs
 *  v == ['','']
 *  // if values entered into the text inputs are 'foo' and 'bar'
 *  v == ['foo','bar']
 *
 *  var v = $(':checkbox').fieldValue();
 *  // if neither checkbox is checked
 *  v === undefined
 *  // if both checkboxes are checked
 *  v == ['B1', 'B2']
 *
 *  var v = $(':radio').fieldValue();
 *  // if neither radio is checked
 *  v === undefined
 *  // if first radio is checked
 *  v == ['C1']
 *
 * The successful argument controls whether or not the field element must be 'successful'
 * (per http://www.w3.org/TR/html4/interact/forms.html#successful-controls).
 * The default value of the successful argument is true.  If this value is false the value(s)
 * for each element is returned.
 *
 * Note: This method *always* returns an array.  If no valid value can be determined the
 *       array will be empty, otherwise it will contain one or more values.
 *
 * @example var data = $("#myPasswordElement").fieldValue();
 * alert(data[0]);
 * @desc Alerts the current value of the myPasswordElement element
 *
 * @example var data = $("#myForm :input").fieldValue();
 * @desc Get the value(s) of the form elements in myForm
 *
 * @example var data = $("#myForm :checkbox").fieldValue();
 * @desc Get the value(s) for the successful checkbox element(s) in the jQuery object.
 *
 * @example var data = $("#mySingleSelect").fieldValue();
 * @desc Get the value(s) of the select control
 *
 * @example var data = $(':text').fieldValue();
 * @desc Get the value(s) of the text input or textarea elements
 *
 * @example var data = $("#myMultiSelect").fieldValue();
 * @desc Get the values for the select-multiple control
 *
 * @name fieldValue
 * @param Boolean successful true if only the values for successful controls should be returned (default is true)
 * @type Array<String>
 * @cat Plugins/Form
 */
$.fn.fieldValue = function(successful) {
    for (var val=[], i=0, max=this.length; i < max; i++) {
        var el = this[i];
        var v = $.fieldValue(el, successful);
        if (v === null || typeof v == 'undefined' || (v.constructor == Array && !v.length))
            continue;
        v.constructor == Array ? $.merge(val, v) : val.push(v);
    }
    return val;
};

/**
 * Returns the value of the field element.
 *
 * The successful argument controls whether or not the field element must be 'successful'
 * (per http://www.w3.org/TR/html4/interact/forms.html#successful-controls).
 * The default value of the successful argument is true.  If the given element is not
 * successful and the successful arg is not false then the returned value will be null.
 *
 * Note: If the successful flag is true (default) but the element is not successful, the return will be null
 * Note: The value returned for a successful select-multiple element will always be an array.
 * Note: If the element has no value the return value will be undefined.
 *
 * @example var data = jQuery.fieldValue($("#myPasswordElement")[0]);
 * @desc Gets the current value of the myPasswordElement element
 *
 * @name fieldValue
 * @param Element el The DOM element for which the value will be returned
 * @param Boolean successful true if value returned must be for a successful controls (default is true)
 * @type String or Array<String> or null or undefined
 * @cat Plugins/Form
 */
$.fieldValue = function(el, successful) {
    var n = el.name, t = el.type, tag = el.tagName.toLowerCase();
    if (typeof successful == 'undefined') successful = true;

    if (successful && (!n || el.disabled || t == 'reset' || t == 'button' ||
        (t == 'checkbox' || t == 'radio') && !el.checked ||
        (t == 'submit' || t == 'image') && el.form && el.form.clk != el ||
        tag == 'select' && el.selectedIndex == -1))
            return null;

    if (tag == 'select') {
        var index = el.selectedIndex;
        if (index < 0) return null;
        var a = [], ops = el.options;
        var one = (t == 'select-one');
        var max = (one ? index+1 : ops.length);
        for(var i=(one ? index : 0); i < max; i++) {
            var op = ops[i];
            if (op.selected) {
                // extra pain for IE...
                var v = $.browser.msie && !(op.attributes['value'].specified) ? op.text : op.value;
                if (one) return v;
                a.push(v);
            }
        }
        return a;
    }
    return el.value;
};


/**
 * Clears the form data.  Takes the following actions on the form's input fields:
 *  - input text fields will have their 'value' property set to the empty string
 *  - select elements will have their 'selectedIndex' property set to -1
 *  - checkbox and radio inputs will have their 'checked' property set to false
 *  - inputs of type submit, button, reset, and hidden will *not* be effected
 *  - button elements will *not* be effected
 *
 * @example $('form').clearForm();
 * @desc Clears all forms on the page.
 *
 * @name clearForm
 * @type jQuery
 * @cat Plugins/Form
 */
$.fn.clearForm = function() {
    return this.each(function() {
        $('input,select,textarea', this).clearFields();
    });
};

/**
 * Clears the selected form elements.  Takes the following actions on the matched elements:
 *  - input text fields will have their 'value' property set to the empty string
 *  - select elements will have their 'selectedIndex' property set to -1
 *  - checkbox and radio inputs will have their 'checked' property set to false
 *  - inputs of type submit, button, reset, and hidden will *not* be effected
 *  - button elements will *not* be effected
 *
 * @example $('.myInputs').clearFields();
 * @desc Clears all inputs with class myInputs
 *
 * @name clearFields
 * @type jQuery
 * @cat Plugins/Form
 */
$.fn.clearFields = $.fn.clearInputs = function() {
    return this.each(function() {
        var t = this.type, tag = this.tagName.toLowerCase();
        if (t == 'text' || t == 'password' || tag == 'textarea')
            this.value = '';
        else if (t == 'checkbox' || t == 'radio')
            this.checked = false;
        else if (tag == 'select')
            this.selectedIndex = -1;
    });
};


/**
 * Resets the form data.  Causes all form elements to be reset to their original value.
 *
 * @example $('form').resetForm();
 * @desc Resets all forms on the page.
 *
 * @name resetForm
 * @type jQuery
 * @cat Plugins/Form
 */
$.fn.resetForm = function() {
    return this.each(function() {
        // guard against an input with the name of 'reset'
        // note that IE reports the reset function as an 'object'
        if (typeof this.reset == 'function' || (typeof this.reset == 'object' && !this.reset.nodeType))
            this.reset();
    });
};


/**
 * Enables or disables any matching elements.
 *
 * @example $(':radio').enabled(false);
 * @desc Disables all radio buttons
 *
 * @name select
 * @type jQuery
 * @cat Plugins/Form
 */
$.fn.enable = function(b) {
    if (b == undefined) b = true;
    return this.each(function() {
        this.disabled = !b
    });
};

/**
 * Checks/unchecks any matching checkboxes or radio buttons and
 * selects/deselects and matching option elements.
 *
 * @example $(':checkbox').selected();
 * @desc Checks all checkboxes
 *
 * @name select
 * @type jQuery
 * @cat Plugins/Form
 */
$.fn.select = function(select) {
    if (select == undefined) select = true;
    return this.each(function() {
        var t = this.type;
        if (t == 'checkbox' || t == 'radio')
            this.checked = select;
        else if (this.tagName.toLowerCase() == 'option') {
            var $sel = $(this).parent('select');
            if (select && $sel[0] && $sel[0].type == 'select-one') {
                // deselect all other options
                $sel.find('option').select(false);
            }
            this.selected = select;
        }
    });
};

})(jQuery);