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   1  // $Id: hoverIntent.js,v 1.1 2009/08/19 04:28:07 sociotech Exp $
   2  
   3  (function($){
   4      /* hoverIntent by Brian Cherne */
   5      $.fn.hoverIntent = function(f,g) {
   6          // default configuration options
   7          var cfg = {
   8              sensitivity: 7,
   9              interval: 100,
  10              timeout: 0
  11          };
  12          // override configuration options with user supplied object
  13          cfg = $.extend(cfg, g ? { over: f, out: g } : f );
  14  
  15          // instantiate variables
  16          // cX, cY = current X and Y position of mouse, updated by mousemove event
  17          // pX, pY = previous X and Y position of mouse, set by mouseover and polling interval
  18          var cX, cY, pX, pY;
  19  
  20          // A private function for getting mouse position
  21          var track = function(ev) {
  22              cX = ev.pageX;
  23              cY = ev.pageY;
  24          };
  25  
  26          // A private function for comparing current and previous mouse position
  27          var compare = function(ev,ob) {
  28              ob.hoverIntent_t = clearTimeout(ob.hoverIntent_t);
  29              // compare mouse positions to see if they've crossed the threshold
  30              if ( ( Math.abs(pX-cX) + Math.abs(pY-cY) ) < cfg.sensitivity ) {
  31                  $(ob).unbind("mousemove",track);
  32                  // set hoverIntent state to true (so mouseOut can be called)
  33                  ob.hoverIntent_s = 1;
  34                  return cfg.over.apply(ob,[ev]);
  35              } else {
  36                  // set previous coordinates for next time
  37                  pX = cX; pY = cY;
  38                  // use self-calling timeout, guarantees intervals are spaced out properly (avoids JavaScript timer bugs)
  39                  ob.hoverIntent_t = setTimeout( function(){compare(ev, ob);} , cfg.interval );
  40              }
  41          };
  42  
  43          // A private function for delaying the mouseOut function
  44          var delay = function(ev,ob) {
  45              ob.hoverIntent_t = clearTimeout(ob.hoverIntent_t);
  46              ob.hoverIntent_s = 0;
  47              return cfg.out.apply(ob,[ev]);
  48          };
  49  
  50          // A private function for handling mouse 'hovering'
  51          var handleHover = function(e) {
  52              // next three lines copied from jQuery.hover, ignore children onMouseOver/onMouseOut
  53              var p = (e.type == "mouseover" ? e.fromElement : e.toElement) || e.relatedTarget;
  54              while ( p && p != this ) { try { p = p.parentNode; } catch(e) { p = this; } }
  55              if ( p == this ) { return false; }
  56  
  57              // copy objects to be passed into t (required for event object to be passed in IE)
  58              var ev = jQuery.extend({},e);
  59              var ob = this;
  60  
  61              // cancel hoverIntent timer if it exists
  62              if (ob.hoverIntent_t) { ob.hoverIntent_t = clearTimeout(ob.hoverIntent_t); }
  63  
  64              // else e.type == "onmouseover"
  65              if (e.type == "mouseover") {
  66                  // set "previous" X and Y position based on initial entry point
  67                  pX = ev.pageX; pY = ev.pageY;
  68                  // update "current" X and Y position based on mousemove
  69                  $(ob).bind("mousemove",track);
  70                  // start polling interval (self-calling timeout) to compare mouse coordinates over time
  71                  if (ob.hoverIntent_s != 1) { ob.hoverIntent_t = setTimeout( function(){compare(ev,ob);} , cfg.interval );}
  72  
  73              // else e.type == "onmouseout"
  74              } else {
  75                  // unbind expensive mousemove event
  76                  $(ob).unbind("mousemove",track);
  77                  // if hoverIntent state is true, then call the mouseOut function after the specified delay
  78                  if (ob.hoverIntent_s == 1) { ob.hoverIntent_t = setTimeout( function(){delay(ev,ob);} , cfg.timeout );}
  79              }
  80          };
  81  
  82          // bind the function to the two event listeners
  83          return this.mouseover(handleHover).mouseout(handleHover);
  84      };
  85      
  86  })(jQuery);