js消除获取值多余的空格

var str = "aa 12  a  1   ";
str = str.replace(/[ ]/g,""); //替换所有空格！ 

==================== 详细点就是 ==================
        var sname = document.getElementsByName("name").value;  
        sname = sname.replace(/[ ]/g,""); //替换所有空格！
        if(sname == "")
        {
        alert("name 输入为空");
        }