default checked radio box in css code example

Example 1: default checked radio button

<input type="radio" name="imgsel" value="" checked>

Example 2: checked radio button css

//html
<input id="rad1" type="radio" name="rad"/><label for="rad1">Radio 1</label>
<input id="rad2" type="radio" name="rad"/><label for="rad2">Radio 2</label>\

//css
input[type="radio"]:checked+label { font-weight: bold; }