When developing Web applications with PHP and MySQL, you end up with potential bugs in one of four or more technologies. You could have HTML issues, PHP problems, SQL errors, or MySQL mistakes. To be able to fix the bug, you must first determine in what realm the bug resides.
HTML problems are often the least disruptive and the easiest to catch. You normally know there’s a problem when your layout is all messed up. Some steps for catching and fixing these, as well as general debugging processes, are discussed in the next section.
PHP errors are the ones you’ll see most often, as this language will be at the heart of your applications. PHP errors fall into three general areas: