JavaScript生成GUID

function newGuid()
        {
var guid = "";
for (var i = 1; i <= 32; i++){
var n = Math.floor(Math.random()*16.0).toString(16);
guid +=   n;
if((i==8)||(i==12)||(i==16)||(i==20))
guid += "-";
            }
return guid;    
        }