Question

I want to increase the value of text field on page load in JavaScript.
For example

<input type="text" name="itemquantity[]" value="1"/>

after pageload it shoud be like

<input type="text" name="itemquantity[]" value="2"/>

Answer 1

You can do this :

<input id="myid" type="text" name="itemquantity[]" value="1"/>
<script>
   localStorage['myid'] =
      document.getElementById('myid').value =
          parseInt(localStorage['myid'] || '0', 10) + 1;
</script>

At each load of the page, the value will be incremented by 1, with initial value being 1.