How to make a field appear upon clicking a checkbox

[Pazman 32]

Try this, see if you can use it.  On a normal web page works perfectly:

 

<span onclick="
if (this.parentNode.getElementsByTagName('img')[0].style.display != '') {
 this.parentNode.getElementsByTagName('img')[0].style.display = '';
 this.innerHTML = '<b>CLICK ME ~~~> </b><a href=\'#\' style=\'text-decoration: none;\' onClick=\'return false;\'>(Spoiler HIDE)</a>';
} 
else {
 this.parentNode.getElementsByTagName('img')[0].style.display = 'none';
 this.innerHTML = '<b>CLICK ME ~~~> </b><a href=\'#\' style=\'text-decoration: none;\' onClick=\'return false;\'>(Spoiler SHOW)</a>';
}
">
<b>CLICK ME ~~~> </b><a href="#" style="text-decoration: none;" onclick="return false;">(Spoiler HIDE)</a></span>
<div>
<img style="max-width: 700px; overflow: hidden;" src="http://www.firefoxgoogletoolbar.com/ff1.jpg" border="0">
</div>

 

 

 

I tried to substitute this with a dropdown or checkbox, any suggestions as to how I can add them in vs, an image?

 

<img style="max-width: 700px; overflow: hidden;" src="http://www.firefoxgoogletoolbar.com/ff1.jpg" border="0">