Javascript/PHP Help. urgent

I am hoping some here can help me with this issue. I am using a Website Builder program to help me build a "members area" of my site. This website builder is very good, I like it a lot, very visual and easy to create pages and organize site. In this website builder I can put code at the: start of the page (either html or php page) inside the tag inside tag After tag Before and End of page. So, I am working on a page now that is pretty complex, I have lots of buttons, some combo boxes, some textarea and test boxes I need to fill in and Buttons I need to preform actions on. The software lets me do Javascript pretty well. I can put some Javascript code with Functions defined inside the tag of the page, then on the Event of "onclick" for a button I can set it to "MyFunc()" my function name, and it will run the code for that function. That works good. I am also doing some PHP code at the top of this page and doing 2 "require_once" statements to bring in some php files, one to connect to the 2 MySql databases I am using, and one to bring in a [login to view URL] file that does some stuff when the page loads, that seems to be working too. Here is my issue, I want to be able to "require_once" a [login to view URL] file also at the top that will bring in PHP functions that I can run when I need to. The problem is, the Website Builder program will not let me point the "onclick" Event to a PHP function. only Javascript functions that I have added inside the tag. So I need a way that I can run a PHP function, but do it with Javascript code. So I can "include" [login to view URL] file with PHP functions defined, then tell the Button to "onclick" run a Javascript function Whatever(), and have that function trigger a PHP function. I have read some stuff about "AJAX" but do not know how to implement that. I am not a Javascript or PHP programmer, just learning and piecing code together to get it to work. I am looking for a simple solution. Not wanting to re writing my whole site or anything. Just a repeatable proceedure that I can use for all the buttons and actions i need to set up. Suggestions are welcome. Thanks,