I should know the content of js

1. 阻止事件传播，必须显示，return false;
   

2. return exp?confirm():!!alert();

3. js 定时器，线程，启动，开始，停止。参数传递，使用window;

4. 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();

};