How to avoid a postback in JavaScript?

Question

I have an ASP.NET page which has a button it it. The button click launches a modal dialog box using JavaScript. Based on the value returned by the modal dialog box, I want to proceed with, or cancel the post back that happens. How do I do this?

Answer 1

Adding "return false;" to the onclick attribute of the button will prevent the automatic postback.

Answer 2

Is this what you are trying to do?

<input type="button" id="myButton" value="Click!" />

<script type="text/javascript">
document.getElementById('myButton').onclick = function() {
    var agree = confirm('Are you sure?');
    if (!agree) return false;
};
</script>