/* 
 *设置Cookie 
 * 
 * name:cookie所对应的键 
 * value:cookie所对应的值 
 * expires:cookie所对应的有效时间 
 * path:指定可访问cookie的路径 
 * domain:指定可访问cookie的主机名 
 * secure:安全性 
 */ 
function setCookie (name,value,expires,path,domain,secure) {   
  //cookie键值对  
  var str = name + "=" + escape(value); 
  //设置cookie的有效期,以小时为单位 
  if(expires > 0){                 
    var date = new Date(); 
    var ms = expires * 3600 * 1000; 
    date.setTime(date.getTime() + ms); 
    str += "; expires=" + date.toGMTString(); 
  } 
  if(path){ 
    str += "; path=" + path; 
  } 
  if(domain){ 
    str += "; domain=" + domain; 
  } 
  if(secure){ 
    str += "; secure"; 
  } 
  document.cookie = str; 
} 
/* 
 *获得Cookie 
 * 
 *cookie_name:cookie的键 
 */ 
function getCookie(cookie_name)  
{    
  var value = null; 
  var allcookies = document.cookie;  
  var cookie_pos = allcookies.indexOf(cookie_name);  
  // 如果找到了索引，就代表cookie存在，  
  // 反之，就说明不存在。  
  if (cookie_pos != -1)  
  {  
    // 把cookie_pos放在值的开始，只要给值加1即可。  
    cookie_pos += cookie_name.length + 1;  
    var cookie_end = allcookies.indexOf(";", cookie_pos);  
    if (cookie_end == -1)  
    {   
      cookie_end = allcookies.length;  
    }  
    value = unescape(allcookies.substring(cookie_pos, cookie_end));  
  }  
  return value;  
}  
/* 
 *删除Cookie 
 * 
 *cookie_name:cookie的键 
 */ 
function delCookie(cookie_name) 
{ 
  var exp = new Date(); 
  exp.setTime(exp.getTime() - 1); 
  var value = getCookie(cookie_name); 
  if(value){ 
    document.cookie= cookie_name + "=" + value + ";expires=" + exp.toGMTString(); 
  } 
}