Q:

onClick toggle radio and label elements

This is what i tried. 
<form method="POST">
<label>YES</label>
<input type="radio" name="yes">
<? php 
if(isset($_POST['yes']) === 'yes'){
? >
<label>Show me on yes</label>
<input type="radio" name="showme">
<? php
}

? >
</form>

So when we select the radio button "YES" than it must show "showme" radio button. 
What do i wrong in here ? 
I want it to show before submitting the form

A:

I guess you are looking for a perhaps front end solution without submitting the data to the server, that is you want to show the radio on check of another radio which can be achieved by client side scripting such as JavaScript or jQuery , but if it's that so than you can achieve that with pure CSS too...
Demo
Demo 2 (With label)
input[id="yes"] {
    display: none;
}

label[for="yes"] {
    display: none;
}

input[id="showyes"]:checked + label[for="yes"] {
    display: block;
}

input[id="showyes"]:checked + label[for="yes"] + input[id="yes"] {
    display: block;
}

Note: JavaScript/jQuery will fail if client has JS Disabled, well yes, JS can be the best way, but why use it if it can be easily accomplished with CSS only..

