Detect left mouse button press

Question

I hate this mess with the mouse buttons created by W3C an MS! I want to know if the left mouse button is pressed when I get a mousedown event.

I use this code

// Return true if evt carries left mouse button press
function detectLeftButton(evt) {
  // W3C
  if (window.event == null) {
    return (evt.button == 0)
  }
  // IE
  else {
    return (evt.button == 1);
  }
}

However, it does not work in Opera and Chrome, because it so happens that window.event exists there too.

So what do I do? I have some browser detection, but we all know it cannot be relied upon with all the masking some browsers do lately. How do I detect the left mouse button RELIABLY?

Answer 1

Updated answer. The following will detect if the left and only the left mouse button is pressed:

function detectLeftButton(evt) {
    evt = evt || window.event;
    if ("buttons" in evt) {
        return evt.buttons == 1;
    }
    var button = evt.which || evt.button;
    return button == 1;
}

For much more information about handling mouse events in JavaScript, try http://unixpapa.com/js/mouse.html