Onselect whileloop, while loop in javascript

<script>
function whileloop() {
 var limitvalue=document.getElementById("limitvalue").value;
 var text = "";
 var i = 1;
 while (i <= limitvalue) {
text += "<br>The number is " + i;
        i++;
    }
    document.getElementById("demo").innerHTML = text;
if(limitvalue.value=='') // use length or value
alert('invalid')
  }
</script>



<h2>Onchange whileloop will work</h2>
<select id='limitvalue' name='limitvalue' onChange="whileloop();">
   <option selected value="0"  >Select</option>
<option>1</option>
   <option>2</option>
   <option>3</option>
<option>4</option>
<option>5</option>
</select>
<p id="demo"></p>