Parse Params Function Stolen

parseparams.js

/**
 * JavaScript Get URL Parameter
 * 
 * @param String prop The specific URL parameter you want to retreive the value for
 * @return String|Object If prop is provided a string value is returned, otherwise an object of all properties is returned
 */
function getParam(str, prop) {
    let params = {};
    let search = decodeURIComponent(str);
    let definitions = search.split( '&' );

    definitions.forEach( function( val, key ) {
        var parts = val.split( '=', 2 );
        params[parts[ 0 ]] = parts[ 1 ];
    } );

    return (prop && prop in params) ? params[ prop ] : params;
}