If you need to get a reference to a class in ActionScript 3, but only know the class name, then you can use the flash.utils.getDefinitionByName to create an instance of the class. For example:

package {
	import flash.display.Sprite;
	import flash.utils.getDefinitionByName;

	public class DynamicCall extends Sprite
	{
		public function DynamicCall()
		{
                    var ClassReference:Class = getDefinitionByName("ClassName") as Class;
		}
	}
}

Example :

var ClassReference:Class = getDefinitionByName("String") as Class;
var str:String = (new ClassReference("SAbi Sin") as String);
trace(str);

This basically creates an instance of the String class, from the class name “String”. getDefinitionByName takes the entire class path, so if you wanted to create an instance of MovieClip, you would provide the entire path:

var ClassReference:Class = getDefinitionByName("flash.display.MovieClip") as Class;

Simple useful Snippet.