src/offset.js

   1 if ( document.documentElement["getBoundingClientRect"] )
   2         jQuery.fn.offset = function() {
   3                 if ( !this[0] ) return { top: 0, left: 0 };
   4                 if ( this[0] === this[0].ownerDocument.body ) return jQuery.offset.bodyOffset( this[0] );
   5                 var box  = this[0].getBoundingClientRect(), doc = this[0].ownerDocument, docElem = doc.documentElement,
   6                         top  = box.top  + (self.pageYOffset || jQuery.boxModel && docElem.scrollTop  || doc.body.scrollTop ) - docElem.clientTop,
   7                         left = box.left + (self.pageXOffset || jQuery.boxModel && docElem.scrollLeft || doc.body.scrollLeft) - docElem.clientLeft;
   8                 return { top: top, left: left };
   9         };
  10 else
  11         jQuery.fn.offset = function() {
  12                 if ( !this[0] ) return { top: 0, left: 0 };
  13                 if ( this[0] === this[0].ownerDocument.body ) return jQuery.offset.bodyOffset( this[0] );
  14                 jQuery.offset.initialized || jQuery.offset.initialize();
  15
  16                 var elem = this[0], offsetParent = elem.offsetParent, prevOffsetParent = elem,
  17                         doc = elem.ownerDocument, computedStyle, docElem = doc.documentElement,
  18                         body = doc.body, defaultView = doc.defaultView,
  19                         prevComputedStyle = defaultView.getComputedStyle(elem, null),
  20                         top = elem.offsetTop, left = elem.offsetLeft;
  21
  22                 while ( (elem = elem.parentNode) && elem !== body && elem !== docElem ) {
  23                         computedStyle = defaultView.getComputedStyle(elem, null);
  24                         top -= elem.scrollTop, left -= elem.scrollLeft;
  25                         if ( elem === offsetParent ) {
  26                                 top += elem.offsetTop, left += elem.offsetLeft;
  27                                 if ( jQuery.offset.doesNotAddBorder && !(jQuery.offset.doesAddBorderForTableAndCells && /^t(able|d|h)$/i.test(elem.tagName)) )
  28                                         top  += parseInt( computedStyle.borderTopWidth,  10) || 0,
  29                                         left += parseInt( computedStyle.borderLeftWidth, 10) || 0;
  30                                 prevOffsetParent = offsetParent, offsetParent = elem.offsetParent;
  31                         }
  32                         if ( jQuery.offset.subtractsBorderForOverflowNotVisible && computedStyle.overflow !== "visible" )
  33                                 top  += parseInt( computedStyle.borderTopWidth,  10) || 0,
  34                                 left += parseInt( computedStyle.borderLeftWidth, 10) || 0;
  35                         prevComputedStyle = computedStyle;
  36                 }
  37
  38                 if ( prevComputedStyle.position === "relative" || prevComputedStyle.position === "static" )
  39                         top  += body.offsetTop,
  40                         left += body.offsetLeft;
  41
  42                 if ( prevComputedStyle.position === "fixed" )
  43                         top  += Math.max(docElem.scrollTop, body.scrollTop),
  44                         left += Math.max(docElem.scrollLeft, body.scrollLeft);
  45
  46                 return { top: top, left: left };
  47         };
  48
  49 jQuery.offset = {
  50         initialize: function() {
  51                 if ( this.initialized ) return;
  52                 var body = document.body, container = document.createElement('div'), innerDiv, checkDiv, table, rules, prop, bodyMarginTop = body.style.marginTop,
  53                         html = '<div style="position:absolute;top:0;left:0;margin:0;border:5px solid #000;padding:0;width:1px;height:1px;"><div></div></div><table style="position:absolute;top:0;left:0;margin:0;border:5px solid #000;padding:0;width:1px;height:1px;"cellpadding="0"cellspacing="0"><tr><td></td></tr></table>';
  54
  55                 rules = { position: 'absolute', top: 0, left: 0, margin: 0, border: 0, width: '1px', height: '1px', visibility: 'hidden' }
  56                 for ( prop in rules ) container.style[prop] = rules[prop];
  57
  58                 container.innerHTML = html;
  59                 body.insertBefore(container, body.firstChild);
  60                 innerDiv = container.firstChild, checkDiv = innerDiv.firstChild, td = innerDiv.nextSibling.firstChild.firstChild;
  61
  62                 this.doesNotAddBorder = (checkDiv.offsetTop !== 5);
  63                 this.doesAddBorderForTableAndCells = (td.offsetTop === 5);
  64
  65                 innerDiv.style.overflow = 'hidden', innerDiv.style.position = 'relative';
  66                 this.subtractsBorderForOverflowNotVisible = (checkDiv.offsetTop === -5);
  67
  68                 body.style.marginTop = '1px';
  69                 this.doesNotIncludeMarginInBodyOffset = (body.offsetTop === 0);
  70                 body.style.marginTop = bodyMarginTop;
  71
  72                 body.removeChild(container);
  73                 this.initialized = true;
  74         },
  75
  76         bodyOffset: function(body) {
  77                 jQuery.offset.initialized || jQuery.offset.initialize();
  78                 var top = body.offsetTop, left = body.offsetLeft;
  79                 if ( jQuery.offset.doesNotIncludeMarginInBodyOffset )
  80                         top  += parseInt( jQuery.curCSS(body, 'marginTop',  true), 10 ) || 0,
  81                         left += parseInt( jQuery.curCSS(body, 'marginLeft', true), 10 ) || 0;
  82                 return { top: top, left: left };
  83         }
  84 };
  85
  86
  87 jQuery.fn.extend({
  88         position: function() {
  89                 var left = 0, top = 0, results;
  90
  91                 if ( this[0] ) {
  92                         // Get *real* offsetParent
  93                         var offsetParent = this.offsetParent(),
  94
  95                         // Get correct offsets
  96                         offset       = this.offset(),
  97                         parentOffset = /^body|html$/i.test(offsetParent[0].tagName) ? { top: 0, left: 0 } : offsetParent.offset();
  98
  99                         // Subtract element margins
 100                         // note: when an element has margin: auto the offsetLeft and marginLeft
 101                         // are the same in Safari causing offset.left to incorrectly be 0
 102                         offset.top  -= num( this, 'marginTop'  );
 103                         offset.left -= num( this, 'marginLeft' );
 104
 105                         // Add offsetParent borders
 106                         parentOffset.top  += num( offsetParent, 'borderTopWidth'  );
 107                         parentOffset.left += num( offsetParent, 'borderLeftWidth' );
 108
 109                         // Subtract the two offsets
 110                         results = {
 111                                 top:  offset.top  - parentOffset.top,
 112                                 left: offset.left - parentOffset.left
 113                         };
 114                 }
 115
 116                 return results;
 117         },
 118
 119         offsetParent: function() {
 120                 var offsetParent = this[0].offsetParent || document.body;
 121                 while ( offsetParent && (!/^body|html$/i.test(offsetParent.tagName) && jQuery.css(offsetParent, 'position') == 'static') )
 122                         offsetParent = offsetParent.offsetParent;
 123                 return jQuery(offsetParent);
 124         }
 125 });
 126
 127
 128 // Create scrollLeft and scrollTop methods
 129 jQuery.each( ['Left', 'Top'], function(i, name) {
 130         var method = 'scroll' + name;
 131
 132         jQuery.fn[ method ] = function(val) {
 133                 if (!this[0]) return;
 134
 135                 return val != undefined ?
 136
 137                         // Set the scroll offset
 138                         this.each(function() {
 139                                 this == window || this == document ?
 140                                         window.scrollTo(
 141                                                 !i ? val : jQuery(window).scrollLeft(),
 142                                                  i ? val : jQuery(window).scrollTop()
 143                                         ) :
 144                                         this[ method ] = val;
 145                         }) :
 146
 147                         // Return the scroll offset
 148                         this[0] == window || this[0] == document ?
 149                                 self[ i ? 'pageYOffset' : 'pageXOffset' ] ||
 150                                         jQuery.boxModel && document.documentElement[ method ] ||
 151                                         document.body[ method ] :
 152                                 this[0][ method ];
 153         };
 154 });