don't over complicate things, the selection is a simple string, treat it like any other string concatenation done in JavaScript
$("div#mainnav .mainnav[alt='" + selectid + "']") thats $ ( double-quote div# alt = single-quote double-quote + selectid + double-quote single- quote ] double-quote On Apr 2, 4:10 pm, mylok <shenxu...@gmail.com> wrote: > code like below: > var selectid = Querystring.get("id"); > $('div#mainnav .mainnav[alt="selectid?"]').addClass("color"); > > I want to select element which attr alt = selectid(variable from > querystring). How can I do that? Thanks.