onclick event in the javascript

I am very new to javascript I know that you can add an onclick=”” event to a html element… but is it possible in the javascript itself to declare that when someone clicks on x element an event is triggered?

Answer

<input id="myElement" type="button" value="Click me!" />
<script type="text/javascript">
    document.getElementById('myElement').onclick = function () {
        alert('Hello, world!');
    }
</script>

Make sure that you either run this after the element already exists (scripts at the bottom), or when the DOM is ready. (You could use window.onload for that, but you might just want to use jQuery from the beginning so that, among other things, you get a magical DOM-ready function. onload has some downsides, like waiting for images to load.)