客户端页面往服务器传数据的简单方法

var url = '/status_tracker.php';
var params = ['step=2', 'time=1248027314'];
var beacon = new Image();
beacon.src = url + '?' + params.join('&');
beacon.onload = function() {
	if (this.width == 1) {
		// Success.
	} else if (this.width == 2) {
		// Failure; create another beacon and try again.
	}
};
beacon.onerror = function() {
	// Error; wait a bit, then create another beacon and try again.
}

原文出自：《High.Performance.JavaScript》