文字列が数値形式であることをチェックするメソッド

/**
 * Copyright asahiufo ( http://wonderfl.net/user/asahiufo )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/dTKM
 */

package {
    import flash.display.Sprite;
    import flash.text.TextField;
    
    public class FlashTest extends Sprite {
        public function FlashTest() {
        		var tracer:TextField = new TextField();
        		addChild(tracer);
        	
            tracer.appendText(checkNumberString("123") + "\n");
            tracer.appendText(checkNumberString("abc") + "\n");
            tracer.appendText(checkNumberString("12.56") + "\n");
            tracer.appendText(checkNumberString("-23") + "\n");
            tracer.appendText(checkNumberString("-98.76") + "\n");
            tracer.appendText(checkNumberString("") + "\n");
        }
        public function checkNumberString(str:String):Boolean
        {
        		if (str.length == 0)
        		{
        			return false;
        		}
        		return !isNaN(Number(str));
        	}
    }
}