this is nothing new but i didn’t learn about it until yesterday and it totally made my day. basically if you use code like:

<label for="checkme">Check me:</label> <input type="checkbox" id="checkme"/>
<br />
<br /> 
<label for="radio1">Radio 1:</label> <input type="radio" id="radio1" name="something" value="on"/> <label for="radio2">Radio 2:</label> <input type="radio" id="radio2" name="something" value="off"/>

clicking on the corresponding label text will check/uncheck the checkbox & radio buttons for you.

click for an example.

as long as the label for attribute matches the id attribute inside of the input tag, clicking on the text always have some type of effect on the input field. mostly just set the focus on the input field. the coolest ones are the checkbox and the radio buttons as you can see in the example.