Replace Variable on Url



Hello,
I have this question about parse url ...

The url is.
lala.com/index.php?page=services&type=development&lang=eng

i want to parse this url so as to able to check it anytime throuh my
pages and replace the lang with

lala.com/index.php?page=services&type=development

I want to use this function in many pages, so as to be able to change
the language anytime.

Thank you.
p.s. i am a newbbie.

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