js设置，取得，清除cookie

//取得cookiefunction getCookie(name) { var nameEQ = name + "="; var ca = document.cookie.split(';'); //把cookie分割成组 for(var i=0;i < ca.length;i++) { var c = ca[i]; //取得字符串 while (c.charAt(0)==' ') { //判断一下字符串有没有前导空格 c = c.substring(1,c.length); //有的话，从第二位开始取 } if (c.indexOf(nameEQ) == 0) { //如果含有我们要的name return unescape(c.substring(nameEQ.length,c.length)); //解码并截取我们要值 } } return false;}//清除cookiefunction clearCookie(name) { setCookie(name, "", -1);}//设置cookiefunction setCookie(name, value, seconds) { seconds = seconds || 0; //seconds有值就直接赋值，没有为0，这个根php不一样。 var expires = ""; if (seconds != 0 ) { //设置cookie生存时间 var date = new Date(); date.setTime(date.getTime()+(seconds*1000)); expires = "; expires="+date.toGMTString(); } document.cookie = name+"="+escape(value)+expires+"; path=/"; //转码并赋值}  setCookie("test","tank",1800); //设置cookie的值，生存时间半个小时alert(getCookie('test')); //取得cookie的值，显示tankclearCookie("test"); //删除cookie的值alert(getCookie('test')); //test对应的cookie值为空，显示为false.就是getCookie最后返的false值。