javascript如何删除Cookie

function getCookie2(name){
    var arr = document.cookie.match(new RegExp("(^| )"+name+"=([^;]*)(;|$)"));  
    if(arr != null) 
        return unescape(arr[2]); 
        return null;
}

function resetNfluent(){
		alert("before=>"+document.cookie);
		var exp  = new Date();
		exp.setTime(exp.getTime() - 1);
		var cval=getCookie2('name');
		var lanObj=document.getElementById('lanOption');
		var lanSel=lanObj.value;
		alert(lanSel);
		if(lanSel=='en'){
			alert('let\'s reset nFluent');
			alert('cval=>'+cval);
			if(cval!=null){
				document.cookie="name="+cval+";
				domain=.example.com;
				expires="+exp.toGMTString()+";
				path=/";
			}else{
				document.cookie="name=;
				domain=.example.com;
				expires="+exp.toGMTString()+";
				path=/";
				}
		}else{
			alert('Don\'t need reset nFluent');
			}
		alert("after=>"+document.cookie);
    }