Paul's JavaScript Examples | ||
Convertor script to convert ° Fahrenheit to ° Celsius and ° Celsius to ° Fahrenheit. Just fill in one value and click on the Convert button. use the Clear button to clear the values. Note, negative values are not supported.
Example
Usage
<INPUT TYPE="button" VALUE="Convert" onClick=computeForm(this.form)> <INPUT TYPE="button" VALUE="Clear" onClick=clearForm(this.form)>
Source
<SCRIPT LANGUAGE="javascript"> <!-- function checkNumber(numStr, fieldName) { msg = fieldName + " field has invalid data: " + numStr.value; str = numStr.value; for (var i=0; i < str.length; i++) { var ch = str.substring(i,i+1); if ( (ch < "0" || ch > "9") && ch != '.' ) { alert(msg); return false; } } return true; } function computeForm(form) { // if both forms empty - error if ( (form.fdegrees.value == null || form.fdegrees.value.length == 0) && (form.cdegrees.value == null || form.cdegrees.value.length == 0) ) { alert("Both fields empty."); return; } // if both forms filled error if ( (form.fdegrees.value != null && form.fdegrees.value.length > 0) && (form.cdegrees.value != null && form.cdegrees.value.length > 0) ) { alert("Error: both fields have data."); return; } // calculate fahrenheit if ( (form.fdegrees.value == null || form.fdegrees.value.length == 0) && (form.cdegrees.value != null && form.cdegrees.value.length > 0) ) { if (checkNumber(form.cdegrees,"Celsius")) { var degs = 0.0 + form.cdegrees.value; degs = (degs * 9.0/5.0) + 32; form.fdegrees.value = degs; } } // calculate celsius if ( (form.fdegrees.value != null && form.fdegrees.value.length > 0) && (form.cdegrees.value == null || form.cdegrees.value.length == 0) ) { if (checkNumber(form.fdegrees,"Fahrenheit")) { var degs = 0.0 + form.fdegrees.value; degs = (degs - 32.0) * (5.0/9.0); form.cdegrees.value = degs; } } } // Used for the temperature conversion function clearForm(form) { form.fdegrees.value=""; form.cdegrees.value=""; } // --> </SCRIPT>