1.设置cookie
function addCookie(name,value,expireHours){
  var cookieString=name+"="+escape(value)+"; path=/";
  //判断是否设置过期时间
  if(expireHours>0){
    var date=new Date();
    date.setTime(date.getTime()+expireHours*3600*1000);
    cookieString=cookieString+";expires="+date.toGMTString();
  }
  document.cookie=cookieString;
}
2.查询cookie
function getCookie(name){
	  var strcookie=document.cookie;
	  var arrcookie=strcookie.split("; ");
	  for(var i=0;i<arrcookie.length;i++){
	    var arr=arrcookie[i].split("=");
	    if(arr[0]==name)return unescape(arr[1]);
	  }
	  return null;
}
3.删除cookie
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+"; path=/;expires="+exp.toGMTString();
}
原文:http://www.cnblogs.com/xiaokele1314/p/7657337.html