阻止事件传播，必须显示，return false;
return exp?confirm():!!alert();
js 定时器，线程，启动，开始，停止。参数传递，使用window;
js扩展：
String.prototype.Trim = String.prototype.trim = function() {
return this.replace(/(^\s*)|(\s*$)/g, "");
};
function StringBuffer() {
this._strings_ = new Array();
}
StringBuffer.prototype.append = function(str) {
this._strings_.push(str);
return this;
};
StringBuffer.prototype.toString = function() {
return this._strings_.join("");
};
Date.prototype.toSimpleString = function() {
return (this.getFullYear() - 2000) + "/" + (this.getMonth() + 1) + "/" + this.getDate() + " " + this.getHours() + ":" + this.getMinutes();
};
