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 panel.

Returns

Nothing.

Description

Statement; evaluates the expression and displays the result in the Output panel in test mode.

Use this action to record programming notes or to display messages in the Output panel while testing a movie. Use the expression parameter to check if a condition exists, or to display values in the Output panel. 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 my_mc must be released on a specific target. A conditional statement evaluates the _droptarget property and executes different actions depending on where my_mc is released. The trace() action is used at the end of the script to evaluate the location of the my_mc movie clip and to display the result in the Output panel. If my_mc doesn't behave as expected (for example, if it snaps to the wrong target), the values sent to the Output panel by the trace() action will help you determine the problem in the script.

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

on(release) {
  if(eval(_droptarget) != target) {
      my_mc._x = my_mc_xValue;
      my_mc._y = my_mc_yValue;
  } else {
    var my_mc_xValue = my_mc._x;
    var my_mc_yValue = my_mc._y;
    target = "_root.pasture";
  }
  trace("my_mc_xValue = " + my_mc_xValue);
  trace("my_mc_xValue = " + my_mc_xValue);
  stopDrag();
}