In a GridView I have a column of checkboxes and a column of textboxes. I wanted to modify the value of the textbox when the checkbox is checked. jQuery is the perfect fit for this. Here is the code I used:

$(function () {
    var $inp = $('input:checkbox');
    $inp.bind('click', function () {
        var textbox = $(":input:text:eq(" + $inp.index(this) + ")");

        if (this.checked == true) {
            textbox.val('123ABC');
            textbox.attr('disabled', 'disabled');
        } else {
            textbox.attr('disabled', '');
        }
    });
});

This post uses ideas from Suprotim Agarwal.