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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();
    }