javascript 的alert的变量输出

<form name="testform" method="post" action="add.php">     
        <input type="text" name="username" id="username"/>
        <input type="text" name="tel" id="tel" />
        <nput type="submit"  name="send" value="提交订单" onclick="return CheckForm()"/>       
</form>
 
//fmcheck.js
 
function CheckForm(){
        var username = document.getElementById("username").value;
        var tel = document.getElementById("tel").value;
 
        var info="您好，您订购的信息为：姓名："+username+"，电话："+tel;
        alert (info);  

}