Javascript - form elements and string concatenation

Totally forgotten how to get round the following problem.

I am trying to insert a variable(value) into a forms.element command to allow me to check particular element by it's name. Code:-

var v_name = "aq1";
if (document.questions.elements[' + v_name + '][0].checked) {

The above just reads the command as v_name not the content, any help appreciated.

Thanks

[response deleted to keep liorean from doing anything rash]

Great link, tho....

http://www.litotes.demon.co.uk/js_info/sq_brackets.html

Heh. try changing it from [' + v_name + '] to plain [v_name]

Ah, cheesebag beat me to it...