IFrame the 'load' event could't get iframe.window object in firefox

[pobear]

IFrame the 'load' event could't get iframe.window object in firefox

var newIFrame = new IFrame({
			'id': 'openFrame',
			'name': 'openFrame',
			'src': this.url,
			'styles': {
				'border': 'none',
				'width': this.options.width,
				'height': this.options.height - 30
			},
			events: {
				'load': function(){
					alert($type($('openFrame').window));				}.bind(this)
			}
		});

alert return false in firefox!