Avoiding radio input getting focus when an input element in its label is selected in Firefox

I have read this question and I am having the same problem:

Put text input inside label for radio button?

Feel free to take a look using Firefox (Chrome and IE8 do not have this problem.):

http://pastehtml.com/view/1dbqqb3.html

I now understand some javascript has to be used to fix this behavior in Firefox.

But I have no idea how to write this piece of codes.

Thanks in advance开发者_如何学JAVA.

Some html:

<input id="radio1" type="radio" />
<input id="text1" onfocus="selectRadioBtn('radio1')" />

The JavaScript:

function selectRadioBtn(id)
{
    document.getElementById(id).checked = true;
}