T > trace

 

trace

Availability

Flash Player 4.

Usage

trace(expression)

Parameters

expression An expression to evaluate. When a SWF file is opened in the Flash authoring tool (via the Test Movie command), the value of the expression parameter is displayed in the Output window.

Returns

Nothing.

Description

Action; evaluates the expression and displays the result in the Output window in test mode.

Use trace to record programming notes or to display messages in the Output window while testing a movie. Use the expression parameter to check if a condition exists, or to display values in the Output window. The trace action is similar to the alert function in JavaScript.

You can use the Omit Trace actions command in Publish Settings to remove trace actions from the exported SWF file.

Example

This example is from a game in which a draggable movie clip instance named rabbi must be released on a specific target. A conditional statement evaluates the _droptarget property and executes different actions depending on where rabbi is released. The trace action is used at the end of the script to evaluate the location of the rabbi movie clip, and display the result in the Output window. If rabbi doesn't behave as expected (for example, if it snaps to the wrong target), the values sent to the Output window by the trace action will help you determine the problem in the script.

on(press) {
	rabbi.startDrag();
}

on(release) {
	if(eval(_droptarget) != target) {
	  	rabbi._x = rabbi_x;
	  	rabbi._y = rabbi_y;
	} else {
		rabbi_x = rabbi._x;
		rabbi_y = rabbi._y;
		target = "_root.pasture";
	}
	trace("rabbi_y = " + rabbi_y);
	trace("rabbi_x = " + rabbi_x);
	stopDrag();
}