Disabling onclick attribute with javascript

Question

How do I disable the other onclick event once one of them has been activated. Both divs are set to display:none; in the CSS. This is probably really simple but I am new to programming.

HTML

<a id="leftbutton" href="#" onclick="showDiv(this.id); return false;">click me</a>
<a id="righttbutton" href="#"onclick="showDiv(this.id); return false;">click me</a>

Javascript

function showDiv(id)
{   
  if(id == "leftbutton"){
     document.getElementById('orangediv').style.display = 'block';
     }else{
     document.getElementById('greendiv').style.display = 'block';
}}

Solution

this should do the trick:

function showDiv(id)
{   
  if(id == "leftbutton"){
     document.getElementById('orangediv').style.display = 'block';
     document.getElementById('righttbutton').onclick = null;
     }else{
     document.getElementById('greendiv').style.display = 'block';
     document.getElementById('leftbutton').onclick = null;
}}

Comments

[Dan Dascalescu]

Duplicate of Remove onclick event from img tag and technically of How can I remove an inline onclick attribute with a bookmarklet? as well.

[ocat]

Thank you. I tried this one first and it did what I was trying to do before.