Mobile number Validation (Contain 10 digit only) using Java Script

HTML File

  
   
  <div class="lbl">Mobile No : </div>
  <div class="ctrl">
       <input type="number" name="con">
       <span id ="err_cn"></span>
  </div>
  

Java Script File

  
   
function con_validation(con)
{
 var numbers = /^([0-9]{10})$/;
    if (con.value.match(numbers))
    {
        document.getElementById("err_cn").innerHTML = "";
        return true;
    }
    else
    {
        var msg = "please enter valid Contact No. ...";
        document.getElementById("err_cn").innerHTML = msg;
        con.focus();
        return false;
    }   
}