Obtener parámetros pasados por medio de JS

get_params.js

var scripts = document.getElementById('#IDENTIFICADOR DE <script>');
var queryString = scripts.src.replace(/^[^\?]+\??/,'');
var params = parseQuery( queryString );

function parseQuery ( query ) {
    var Params = new Object ();
    if ( ! query ) return Params; // return empty object
    var Pairs = query.split(/[;&]/);
    for ( var i = 0; i < Pairs.length; i++ ) {
        var KeyVal = Pairs[i].split('=');
        if ( ! KeyVal || KeyVal.length != 2 ) continue;
        var key = unescape( KeyVal[0] );
        var val = unescape( KeyVal[1] );
        val = val.replace(/\+/g, ' ');
        Params[key] = val;
    }
    return Params;
}