How to check if a query string value is present via JavaScript?

Question

How can I check if the query string contains a q= in it using JavaScript or jQuery?

Answer 1

one more variant, but almost the same as Gumbos solution:

var isDebug = function(){
    return window.location.href.search("[?&]debug=") != -1;
};

Answer 2

I've used this library before which does a pretty good job of what you're after. Specifically:-

qs.contains(name)
    Returns true if the querystring has a parameter name, else false.

    if (qs2.contains("name1")){ alert(qs2.get("name1"));}

Answer 3

This should help:

function getQueryParams(){
    try{
        url = window.location.href;
        query_str = url.substr(url.indexOf('?')+1, url.length-1);
        r_params = query_str.split('&');
        params = {}
        for( i in r_params){
            param = r_params[i].split('=');
            params[ param[0] ] = param[1];
        }
        return params;
    }
    catch(e){
       return {};
    }
}

Answer 4

You could also use a regular expression:

/[?&]q=/.test(location.search)