Can anybody let me know what happen basically alter the arg_separator.input directive in php.ini file and hang it to 'a' and my form have two text fileds named "title and age" . Then basically submit after that it url is going to be like www.yourdomain.com?title=tempaage=12 did this confuse the server or it'll run fine. Can there be any rule to possess only specific character as arg separator.

Then basically submit after that it url is going to be like www.yourdomain.com?title=tempaage=12

Why is you state that the browser will be sending this type of string towards the server? It will not, it'll simply employ & because the separator as suggested here. If you are planning to create Web addresses yourself, try encoding your example data such as this:

www.yourdomain.com?n%61me=tempa%61ge=12