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, body = doc.body, docElem = doc.documentElement,
   6                         clientTop = docElem.clientTop || body.clientTop || 0, clientLeft = docElem.clientLeft || body.clientLeft || 0,
   7                         top  = box.top  + (self.pageYOffset || jQuery.boxModel && docElem.scrollTop  || body.scrollTop ) - clientTop,
   8                         left = box.left + (self.pageXOffset || jQuery.boxModel && docElem.scrollLeft || body.scrollLeft) - clientLeft;
   9                 return { top: top, left: left };
  10         };
  11 else
  12         jQuery.fn.offset = function() {
  13                 if ( !this[0] ) return { top: 0, left: 0 };
  14                 if ( this[0] === this[0].ownerDocument.body ) return jQuery.offset.bodyOffset( this[0] );
  15                 jQuery.offset.initialized || jQuery.offset.initialize();
  16
  17                 var elem = this[0], offsetParent = elem.offsetParent, prevOffsetParent = elem,
  18                         doc = elem.ownerDocument, computedStyle, docElem = doc.documentElement,
  19                         body = doc.body, defaultView = doc.defaultView,
  20                         prevComputedStyle = defaultView.getComputedStyle(elem, null),
  21                         top = elem.offsetTop, left = elem.offsetLeft;
  22
  23                 while ( (elem = elem.parentNode) && elem !== body && elem !== docElem ) {
  24                         computedStyle = defaultView.getComputedStyle(elem, null);
  25                         top -= elem.scrollTop, left -= elem.scrollLeft;
  26                         if ( elem === offsetParent ) {
  27                                 top += elem.offsetTop, left += elem.offsetLeft;
  28                                 if ( jQuery.offset.doesNotAddBorder && !(jQuery.offset.doesAddBorderForTableAndCells && /^t(able|d|h)$/i.test(elem.tagName)) )
  29                                         top  += parseInt( computedStyle.borderTopWidth,  10) || 0,
  30                                         left += parseInt( computedStyle.borderLeftWidth, 10) || 0;
  31                                 prevOffsetParent = offsetParent, offsetParent = elem.offsetParent;
  32                         }
  33                         if ( jQuery.offset.subtractsBorderForOverflowNotVisible && computedStyle.overflow !== "visible" )
  34                                 top  += parseInt( computedStyle.borderTopWidth,  10) || 0,
  35                                 left += parseInt( computedStyle.borderLeftWidth, 10) || 0;
  36                         prevComputedStyle = computedStyle;
  37                 }
  38
  39                 if ( prevComputedStyle.position === "relative" || prevComputedStyle.position === "static" )
  40                         top  += body.offsetTop,
  41                         left += body.offsetLeft;
  42
  43                 if ( prevComputedStyle.position === "fixed" )
  44                         top  += Math.max(docElem.scrollTop, body.scrollTop),
  45                         left += Math.max(docElem.scrollLeft, body.scrollLeft);
  46
  47                 return { top: top, left: left };
  48         };
  49
  50 jQuery.offset = {
  51         initialize: function() {
  52                 if ( this.initialized ) return;
  53                 var body = document.body, container = document.createElement('div'), innerDiv, checkDiv, table, rules, prop, bodyMarginTop = body.style.marginTop,
  54                         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>';
  55
  56                 rules = { position: 'absolute', top: 0, left: 0, margin: 0, border: 0, width: '1px', height: '1px', visibility: 'hidden' };
  57                 for ( prop in rules ) container.style[prop] = rules[prop];
  58
  59                 container.innerHTML = html;
  60                 body.insertBefore(container, body.firstChild);
  61                 innerDiv = container.firstChild, checkDiv = innerDiv.firstChild, td = innerDiv.nextSibling.firstChild.firstChild;
  62
  63                 this.doesNotAddBorder = (checkDiv.offsetTop !== 5);
  64                 this.doesAddBorderForTableAndCells = (td.offsetTop === 5);
  65
  66                 innerDiv.style.overflow = 'hidden', innerDiv.style.position = 'relative';
  67                 this.subtractsBorderForOverflowNotVisible = (checkDiv.offsetTop === -5);
  68
  69                 body.style.marginTop = '1px';
  70                 this.doesNotIncludeMarginInBodyOffset = (body.offsetTop === 0);
  71                 body.style.marginTop = bodyMarginTop;
  72
  73                 body.removeChild(container);
  74                 this.initialized = true;
  75         },
  76
  77         bodyOffset: function(body) {
  78                 jQuery.offset.initialized || jQuery.offset.initialize();
  79                 var top = body.offsetTop, left = body.offsetLeft;
  80                 if ( jQuery.offset.doesNotIncludeMarginInBodyOffset )
  81                         top  += parseInt( jQuery.curCSS(body, 'marginTop',  true), 10 ) || 0,
  82                         left += parseInt( jQuery.curCSS(body, 'marginLeft', true), 10 ) || 0;
  83                 return { top: top, left: left };
  84         }
  85 };
  86
  87
  88 jQuery.fn.extend({
  89         position: function() {
  90                 var left = 0, top = 0, results;
  91
  92                 if ( this[0] ) {
  93                         // Get *real* offsetParent
  94                         var offsetParent = this.offsetParent(),
  95
  96                         // Get correct offsets
  97                         offset       = this.offset(),
  98                         parentOffset = /^body|html$/i.test(offsetParent[0].tagName) ? { top: 0, left: 0 } : offsetParent.offset();
  99
 100                         // Subtract element margins
 101                         // note: when an element has margin: auto the offsetLeft and marginLeft
 102                         // are the same in Safari causing offset.left to incorrectly be 0
 103                         offset.top  -= num( this, 'marginTop'  );
 104                         offset.left -= num( this, 'marginLeft' );
 105
 106                         // Add offsetParent borders
 107                         parentOffset.top  += num( offsetParent, 'borderTopWidth'  );
 108                         parentOffset.left += num( offsetParent, 'borderLeftWidth' );
 109
 110                         // Subtract the two offsets
 111                         results = {
 112                                 top:  offset.top  - parentOffset.top,
 113                                 left: offset.left - parentOffset.left
 114                         };
 115                 }
 116
 117                 return results;
 118         },
 119
 120         offsetParent: function() {
 121                 var offsetParent = this[0].offsetParent || document.body;
 122                 while ( offsetParent && (!/^body|html$/i.test(offsetParent.tagName) && jQuery.css(offsetParent, 'position') == 'static') )
 123                         offsetParent = offsetParent.offsetParent;
 124                 return jQuery(offsetParent);
 125         }
 126 });
 127
 128
 129 // Create scrollLeft and scrollTop methods
 130 jQuery.each( ['Left', 'Top'], function(i, name) {
 131         var method = 'scroll' + name;
 132
 133         jQuery.fn[ method ] = function(val) {
 134                 if (!this[0]) return null;
 135
 136                 return val !== undefined ?
 137
 138                         // Set the scroll offset
 139                         this.each(function() {
 140                                 this == window || this == document ?
 141                                         window.scrollTo(
 142                                                 !i ? val : jQuery(window).scrollLeft(),
 143                                                  i ? val : jQuery(window).scrollTop()
 144                                         ) :
 145                                         this[ method ] = val;
 146                         }) :
 147
 148                         // Return the scroll offset
 149                         this[0] == window || this[0] == document ?
 150                                 self[ i ? 'pageYOffset' : 'pageXOffset' ] ||
 151                                         jQuery.boxModel && document.documentElement[ method ] ||
 152                                         document.body[ method ] :
 153                                 this[0][ method ];
 154         };
 155 });