Judging by the code you posted, something in the missing code should be wronge. I put your code in jsfiddle ( 1 ) and it works like a charm.
According to w3schools, checked="checked" correct (http://www.w3schools.com/tags/att_input_checked.asp). I often use <input type="radio" "name="foo" checked /> , which also works.
Additional information about the site will be helpful.
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