Modal Popup in Sharepoint by javascript

Most come requirement in Sharepoint custom developemt is to have a popup .This can be achieved by using the Modal PopUp .Below is the code script which gives us popup in sharepoint

<script type=”text/javascript”>

function OpenDialog(URL) {

     var options = SP.UI.$create_DialogOptions();

     options.url = URL;

     options.width = 600;

     options.height = 400;

     SP.UI.ModalDialog.showModalDialog(options);

}

</script>

<a href=”javascript:OpenDialog(‘URL of the page to be displayed here’)”>Link</a>

You can use this script in a .js file reference it anywhere in the sharepoint site and you should be able to call the function .