How do you tell if someone is the developer?

Hi,

How can you know if a person is indeed the developer of a script that you like to purchase.
What proof can you ask, i know that software has source code but what about scripts in php???

There isn't, it's just a text file, I suppose you could ask them about the inner workings but essentially the answer to your question is you can't. Sorry.
Posted via Mobile Device

this goes for pretty much all source code i'm afraid.

as mward stated your best bet is to basically interview them about the script you're purchasing. however if you are purchasing something chances are your level of understanding of the details of the actual language and functionality are not that great.

you could also hit google and see if you can find anything similar to what you are planning on buying?

once you buy the script you can open it up with textpad and look and see if the developer tagged the script. If someones else s name is on it. Back charge the ahole that sold it to you and try contacting the org developer.

There really isnt a way to know for sure since plagiarism exists in almost anything.
Anyone with basic knowledge can rewrite the comments within the script that would claim they are an author of it.... But for a lazy plagiarist that is one way to catch them.
The best way is as mward stated and just interview them on the inner workings of the script. Some more knowledgable developers will also have class diagrams and flowcharts etc.