Somewhere at the beginning of your script (probably on the button's click event), set the button's disabled attribute to true:

$(#mybutton).attr(disabled, true);

Then, when complete, remove that attribute:

$(#mybutton).removeAttr(disabled);

EDIT:

If you want to get (slightly) fancy, change the text of the button while you're doing the work. If it's an image button, you can change the src to a friendly please wait message. Here's an example of the button text version:

$(#mybutton).click(function() {

  var origVal = $(this).attr(value);



  $(this).attr(value, Please wait...);

  $(this).attr(disabled, true);



  //Do your processing.



  $(this).removeAttr(disabled);

  $(this).attr(value, origVal);

});