javaScriptのページの値

function getURIParam(name) {
    var search = window.location.search;
    search = search.substring(1);
    if (search.length < 1) {
        return null;
    }
    var pars = search.split("&");
    for ( var idx in pars) {
        var par = pars[idx];
        var keyval = par.split("=");
        if (keyval.length < 2) {
            continue;
        }
        if (keyval[0].toLowerCase() == name.toLowerCase()) {
            if(keyval.length == 2){
                return keyval[1];
            }
            var res = "";
            for(var i=1;i<keyval.length;i++){
                res += keyval[i] + "=";
            }
            return res.substring(0, res.length - 1);
        }
    }
    return null;
}