Check a radio button with javascript

Question

For some reason, I can\'t seem to figure this out.

I have some radio buttons in my html which toggles categories:

Answer 1

Easiest way would probably be with jQuery, as follows:

$(document).ready(function(){
  $("#_1234").attr("checked","checked");
})

This adds a new attribute "checked" (which in HTML does not need a value). Just remember to include the jQuery library: