Javascript form parser

I am trying to make a generic form parser for Javascript. The idea being, a developer could drop the function onto a form and sumbit via AJAX, or do something with a form besides submit it. The result will be in the same format used in a query string.

What I have posted works, so I am basically wondering if this is a good design? What could be improved? Thanks for the help!

function test_submit(id){
    var results=[],form=document.getElementById(id);
    for(var i=0;i<form.elements.length;++i){
        var obj=form.elements[i];
        if(obj.name&&!obj.disabled){
            switch(obj.tagName){
            case 'SELECT':
                for(var j=0;j<obj.length;++j){
                    if(obj.options[j].selected){
                        var value=obj.options[j].value;
                        if(!value)value=obj.options[j].text;
                        results.push(obj.name+'='+escape(value));
                    }
                }
                break;
            case 'INPUT':
            case 'TEXTAREA':
                var type=obj.type,value=obj.value;
                if(type)type=type.toLowerCase();
                if(type&&(type=='radio'||type=='checkbox')){
                    if(obj.checked)results.push(obj.name+'='+(value?escape(value):'on'));
                }
                else results.push(obj.name+'='+escape(value));
                break;
            }
        }
    }
    return results.join('&');
}

I'd change two things. I'd start by declaring your var's in one statement like so:

function test_submit(id){
    var q=[],
        p=$(id).getElementsByTagName('SELECT');

Second I'd use more descriptive variable names than i, p, r, n. If you run this code through a minifier it'll do this for you. When you come back to edit this code in a few months you'll want to know exactly what each variable is for, and using a descriptive name helps with that.

I'd also be leary of using $ in the global namespace as a variable name since a lot of the popular libraries use it and you don't want to have any collisions with those.

StackExchange Code Review Q#5085, answer score: 3