JavaScript: left or right button?

Left vs. Right Button

This page is obsolete and retained for archival purposes only.
Please use the updated version: Left vs Middle vs Right Mouse Button.

Question: How do I check whether the user clicked the left or right mouse button?

Answer: The click event occurs for the left mouse button only. Therefore, onClick event handlers do not need to preform the left-versus-right button test.

On the other hand, the mousedown and mouseup events may occur for any mouse button. To determine whether the user clicked the left or right button, you can use the following event properties:

event.which in Netscape Navigator

event.button in Internet Explorer

If the value of these properties is 1, the event occurred for the left button. In the following example, the onMouseDown event handler displays the messages Left button or Right button, depending on the mouse button you actually have clicked. The messages will appear on your browser's status bar. Click or right-click anywhere on this page to see it work:

<script language="JavaScript">
<!--
function mouseDown(e) {
 if (parseInt(navigator.appVersion)>3) {
  var clickType=1;
  if (navigator.appName=="Netscape") clickType=e.which;
  else clickType=event.button;
  if (clickType==1) self.status='Left button!';
  if (clickType!=1) self.status='Right button!';
 }
 return true;
}
if (parseInt(navigator.appVersion)>3) {
 document.onmousedown = mouseDown;
 if (navigator.appName=="Netscape") 
  document.captureEvents(Event.MOUSEDOWN);
}
//-->
</script>