How would I clear the text in my google search box when it is clicked and return when unclicked

There is NO unclicked. From your example I understood that you want to put back "Search Google..." when input text box loses focus (user clicks away from the input text box).

But you might want to put back the default text (Search Google...) only if the user does not enter any value in the text box and clicks away. Also you might want to clear the text only if it is not your default text in the text box.

Here are the links for click and blur event handlers in jQuery.

https://api.jquery.com/click/[^]
https://api.jquery.com/blur/[^]

For getting and setting value of input, refer the .val() function of jQuery.
http://api.jquery.com/val/[^]

Since you have used name attribute, you can use attribute selector to find the control and add the event to it.

https://api.jquery.com/attribute-equals-selector/[^]

Code Sample:
Click event with attribute selector:

$("input[name='q']").click(function(){
  //your code
});