Is it possible to trigger a PHP function by just clicking a link? Or should I stick with the form submit method? If clicking the link will work, where should the link refer
You can do this by means of loading the entire page over again by the use of form submission, or by loading specific page contents directly into the page without needing to go from page to page. The second method is called "AJAX" (Asynchoronous Javascript and XML). Here are two examples, one of each specified.
Form submission approach
form.php
...
AJAX approach
ajax_file.php
form.html
click to call function