title: which mouse key is pressed in mousemove() event handler?
body: <p>I use JQuery 1.7 for handling events. </p>
  
  <pre><code>function objToStr(obj) {
      return ...string representation of the object
  }
  $slider.mousedown(function(e) {
      console.log("$slider.mousedown:\n" + objToStr(e) );
  });
  
  $slider.mousemove( function(e) {
      console.log("$slider.mousemove:\n" + objToStr(e) );
  });
  </code></pre>
  
  <p>and here is the result:</p>
  
  <pre><code>$slider.mousedown: 
  altKey = false
   attrChange = undefined 
  attrName = undefined 
  bubbles = true 
  button = 0 
  buttons = undefined 
  cancelable = true 
  clientX = 319 
  clientY = 13 
  ctrlKey = false 
  currentTarget = object 
  data = null 
  delegateTarget = object 
  eventPhase = 3 
  fromElement = undefined 
  handleObj = object
  isDefaultPrevented = (function) 
  isImmediatePropagationStopped = (function) 
  isPropagationStopped = (function) 
  jQuery17209754494933906718 = true 
  metaKey = false 
  offsetX = undefined 
  offsetY = undefined 
  originalEvent = object 
  pageX = 319 
  pageY = 13 
  preventDefault = (function) 
  relatedNode = undefined 
  relatedTarget = null 
  screenX = 2876 
  screenY = 223 
  shiftKey = false 
  srcElement = undefined 
  stopImmediatePropagation = (function) 
  stopPropagation = (function) 
  target = object 
  timeStamp = 869699957 
  toElement = undefined 
  type = "mousedown" 
  view = object 
  which = 1
  
  
  $slider.mousemove: 
  currentTarget = object
  data = null 
  delegateTarget = object 
  exclusive = undefined 
  handleObj = object 
  isDefaultPrevented = (function) 
  isImmediatePropagationStopped = (function) 
  isPropagationStopped = (function) 
  isTrigger = true 
  jQuery17209754494933906718 = true 
  namespace = "" 
  namespace_re = null 
  preventDefault = (function) 
  result = undefined 
  stopImmediatePropagation = (function) 
  stopPropagation = (function) 
  target = object 
  timeStamp = 1334151903323 
  type = "mousemove"
  </code></pre>
  
  <p>I need to access <code>e.which</code> for <code>mousemove</code> but apparently it is not passed to the event handler? </p>
  
  <p>I don't want to use the <strong>flag</strong> algorithm suggested in <a href="https://stackoverflow.com/questions/4065992/jquery-detecting-pressed-mouse-button-during-mousemove-event">jQuery: Detecting pressed mouse button during mousemove event</a>. Because if the user drags the mouse button outside the browser window and release it there, when the mouse comes back to the browser window, it is still thought to be pressed. Then I have to add handlers for when the mouse leaves the window as well and it's too much. Is there a simpler way to know which mouse button is pressed in the event handler of <code>mousemove()</code>?</p>