Coding & scripting: JavaScript: checkbox value

JavaScript: checkbox value

Hi,
I got a site whit some checkbox-es whit some value-es.

I really want to extract the value of only checked checkboxes and put them ni my script bellow.

Here are some of my checkboxes:

> <input type="checkbox" value="a=sweb&" /> Web results
> <input type="checkbox" value="a=simage&" /> Image results

...and from this I only want to get the value from the checked checkboxes (there are some more than showed abou) an put the valu in the script bellow:

> function goTo() {
> var searchInput = document.getElementById("searchInput");
> var url = 'http://a9.com/' +
> encodeURI(searchInput.value.replace(/[\s]/gi, '+')) + '?' + ALL-CHECKED-CHECKBOX-VALUES-HERE.value;
>
> }

But how do I do this?