how to validate cell number
<p>i have to validate the cell no and my requirements are :</p>

<p>1.filed must not empty
2. if user enter alphabetic value it pop-up "alphabets are not allowed"
3. field must start with "+" sign
4. if filed value is less than 13 it pop-up "please enter valid phone no"</p>

<p>i am using this code..</p>

<pre><code>function validateForm()
{

    var cell = document.reg_form.cellno.value;
            if(cell.length==0) 
            {
                alert("Please enter cell number");
                reg_form.cellno.focus();
                return false;
            }

           if(isNaN(cell)||cell.indexOf(" ")!=-1)
              {
                 alert("Enter numeric value")
                 return false; 
              }


            if (cell.charAt(0)!="+")
              {
                alert("Cell no should start with +");
                return false
              }

                if(cell.length &lt; 13) 
               {
              alert("You have entered wrong number");
              reg_form.cellno.focus();
              return false;
        }
return true;
}
</code></pre>

<p>some code is not working here
when i enter numeric value.. it shows {"Cell no should start with "+"}
when i put {+} sign it says please enter numeric value
when i enter only single numeric value like {9} it goes forward.. although in this way field has only 2 value "+" and "9".. it should pop-up {"You have entered wrong number"} </p>

<p>please tell me where i made the mistake....   </p>
