I am not sure if this is the right place to post this, but I didn't find better place, I have a problem I lost my php programmer and my site needs some change and I am not sure to give the work to another programmer, do you think that is easy for a programmer to work with a php that he didn't do? what would be the worst that could happen giving the work to another programmer?
I would say there shouldnt be a problem as long as the guy you hire is capable of doing the job. Just make sure your other programmer isnt going to get mad because you are going to hire someone else!
Well it will also depend on how well the php code was structured and commented. I have completely rewritten sections of code from other programmers, because it was faster than trying to understand what they were doing.
No, they generally will be able to fix your problems. It only depends on the previous programmers job. If it's unorganized, then you are in trouble, if not, then your fine. If your first programmer had written a really big amount of stuff which is hard to understand (no commenting, no structure, etc) then it'll be a pain in the ass for the next programmer. He might have to spend some of his time to understand and start commenting or rewriting "stupid" parts depending on how he feels about the code.
but do you think that my old programmer could get access to the site and if he could is a possibility to know that?
well, if you gave enough info to your old programmer so he has control over your stuff, he could, but you could change your password and you'd be fine. You just have to make sure that what he knew isn't anymore and you should be okay. I can't really say you'll be 100% safe cause I don't know the situation completely.
Yes, a programmer can know his script's weaknesses in term of security (either he didn't feel like securing it or let it weak on purpose) and use that to break your site if he feels you've been abusing him. If the new programer spots security weaknesses and fix them, then it's ok.