How can I do this in jQuery

How can I do this in jQuery

Hello,

I've got a bit of Ajax that I modified from a tutorial ( http://www.tizag.com/ajaxTutorial/ajax-javascript.php)

Code:
  1. <script language="javascript" type="text/javascript">
  2. <!-- 
  3. //Browser Support Code
  4. function ajaxFunction(){
  5. var ajaxRequest;  // The variable that makes Ajax possible!
  6. try{
  7. // Opera 8.0+, Firefox, Safari
  8. ajaxRequest = new XMLHttpRequest();
  9. } catch (e){
  10. // Internet Explorer Browsers
  11. try{
  12. ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
  13. } catch (e) {
  14. try{
  15. ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
  16. } catch (e){
  17. // Something went wrong
  18. alert("Your browser broke!");
  19. return false;
  20. }
  21. }
  22. }
  23. // Create a function that will receive data sent from the server
  24. ajaxRequest.onreadystatechange = function(){
  25. if(ajaxRequest.readyState == 4){
  26. var ajaxDisplay = document.getElementById('ajaxDiv');
  27. ajaxDisplay.innerHTML = ajaxRequest.responseText;
  28. }
  29. }
  30. var course_level = document.getElementById('txtCourseLevel').value;
  31. ajaxRequest.open("GET", "get_courses.php?cl=" + course_level, true);
  32. ajaxRequest.send(null); 
  33. }

  34. //-->
  35. </script>
I would like to do this in jQuery but I'm not sure where to start.

Essentially, when I click a button, it takes the values from my form and sends it to get_courses.php?cl=X and then returns the contents of that page and puts it into a div on the original page.

Thanks, Mark