How to execute if condition based on a value from query string in javascript/jquery?

I've a variable called url as follows :

url = "http://56.177.59.250/static/ajax.php?core[ajax]=true&core[call]=prj_name.contactform&width=400&core[security_token]=c7854c13380a26ff009a5cd9e6699840"

Now I want to use if condition only if core[call] is equal to the value it currently has i.e. prj_name.contactform otherwise not.

How should I do this since the parameter from query-string is in array format?

Please help me.

Thanks.