Question

How to rewrite the code using jQuery?

 <script type="text/javascript">
    window.onload = function(){
        var array = document.getElementsByTagName('div');
        for (var i=0; i<array.length; i++) {
            (function(i) {
                array[i].onclick = function() {
                    alert(i);
                }
            })(i);
        }
    };
    </script>
    <div>0</div>
    <div>1</div>

Thanks…

Answer 1

If you actually want to alert the index:

Example: http://jsfiddle.net/Ksyr6/

   // Wrapping your code in an anonymous function that is passed as a parameter
   //    to jQuery will ensure that it will not run until the DOM is ready.
   // This is a shortcut for jQuery's .ready() method
$(function() {
    $('div').each(function( i ) {
         $(this).click(function() {
            alert( i );
         });
     });
});

This finds all elements with the tag name 'div', and iterates over them, individually assigning a click event that alerts its index.

Or if the index is not important, it becomes simpler:

Example: http://jsfiddle.net/Ksyr6/1/

$(function() {
    $('div').click(function() {
         // You have access to the element that received the event via "this"
         // alert(this.id) will alert the ID of the element that was clicked
        alert( 'i was clicked' );
     });
});

Here the same iteration is taking place, but it is implicit. jQuery iterates over the 'div' elements, giving each on the click event handler that fires an alert.

This is a nice feature of jQuery. You pass it a CSS selector, it finds matching elements, and iterates over them automatically, firing whatever method you call.