Specifying files to act upon in grep

I use the following command: because I want to search recursively the contents of all .php files containing the phrase "dperson_bridge" and it returns nothing.
Then I use the following command: and I receive the kind of output I expect to receive.
Why doesn't the *.php work? I don;t want grep to look into .css or .js files.

Thanks,

Because the shell expands wildcards, not grep. As far as grep is concerned you passed it all the filenames matching the pattern ./*.php (ie, all .php files in the current directory).

There might be an easier way but I use

(find all *.php files and execute "grep dperson_bridge file" on each)