JavaScript get url segment and parameter

var URL='example.com/event/14aD9Uxp?p=10';

var arr=URL.split('/');//arr[0]='example.com'
                       //arr[1]='event'
                       //arr[2]='14aD9Uxp?p=10'

var parameter=arr[arr.length-1].split('?');//parameter[0]='14aD9Uxp'
                                           //parameter[1]='p=10'

var p_value=parameter[1].split('=')[1];//p_value='10';

I've created a generalized function (restricted in some ways) that will return the GET value given the parameter. However this function will only work correctly provided that you do not Rewrite the URL or modify the URL GET SYNTAX.

//Suppose this is your URL "example.com/event/14aD9Uxp?p=10";
            function GET(variable) {
                var str = window.location.href;


                str = str.split("/");
                // str = [example.com, event, 14aD9Uxp?p=10]


                //Get last item from array because this is usually where the GET parameter is located, then split with "?"
                str = str[str.length - 1].split("?");
                // str[str.length - 1] = "14aD9Uxp?p=10"
                // str[str.length - 1].split("?") = [14aD9Uxp, p=10]

                // If there is more than 1 GET parameter, they usually connected with Ampersand symbol (&). Assuming there is more, we need to split this into another array

                str = str[1].split("&");
                // Suppose this is your URL: example.com/event/14aD9Uxp?p=10&q=112&r=119
                // str = [p=10, q=112, r=119]
                // If there is only 1 GET parameter, this split() function will not "split" anything

                //Remember, there might only be 1 GET Parameter, so lets check length of the array to be sure.
                if (str.length > 1) {
                    
                    // This is the case where there is more than 1 parameter, so we loop over the array and filter out the variable requested
                    for (var i = 0; i < str.length; i++) {

                        // For each "p=10" etc. split the equal sign 
                        var param_full_str = str[i].split("=");
                        // param_full_str = [p, 10]

                        //Check if the first item in the array (your GET parameter) is equal to the parameter requested
                        if (param_full_str[0] == variable) {
                            // If it is equal, return the second item in the array, your GET parameter VALUE
                            return param_full_str[1];
                        }
                    }
                } else {
                    // This is the case where there is ONLY 1 GET parameter. First convert it to a String Type because Javascript decided that str was no longer a String
                    // Now split it with the equal sign.
                    str = str.toString().split("=");
                    return str[1];
                }
            }
            document.write(GET("p"));