function 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cookie  
 function clearCookie(name) {  
  setCookie(name, "", -1);  
 }  
   
 //设置cookie  
 function 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  
 }