box==“checkBox  ‘是否记住用户密码’”；

window.onload=function init()
{
 
 var box = getCookie("box_"+str);
 var username = getCookie("usn_"+str);
 var password = getCookie("pwd_"+str);
 if(box==‘yes‘)
 {
  form1.box.checked=true;
  form1.loginName.value=http://www.mamicode.com/username;
  form1.password.value=http://www.mamicode.com/password;
 }

if(form1.box.checked)
  {
   SetCookie("usn_"+str,form1.loginName.value);
   SetCookie("pwd_"+str,form1.password.value);
   SetCookie("box_"+str,"yes");
  }else{
   delCookie("box_"+str);
  }

function SetCookie(name,value)//两个参数，一个是cookie的名子，一个是值
{
    var Days = 300; //此 cookie 将被保存 30 天
    var exp  = new Date();    //new Date("December 31, 9998");
    exp.setTime(exp.getTime() + Days*24*60*60*1000);
    document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString();
}
function getCookie(name)//取cookies函数       
{
    var arr = document.cookie.match(new RegExp("(^| )"+name+"=([^;]*)(;|$)"));
     if(arr != null) return (arr[2]); return null;

}
function delCookie(name)//删除cookie
{
    var exp = new Date();
    exp.setTime(exp.getTime() - 1);
    var cval=getCookie(name);
    if(cval!=null) document.cookie= name + "="+cval+";expires="+exp.toGMTString();

(转)html中 cookie设置