Pass style declarations around for performance improvements and paving the way...

Pass style declarations around for performance improvements and paving the way for the css array signature
Also, simplify the jQuery.css numeric coercion signature

src/css.js

-var curCSS, iframe,
+var curCSS, getStyles, iframe,
 	ralpha = /alpha\([^)]*\)/i,
 	ropacity = /opacity\s*=\s*([^)]*)/,
 	rposition = /^(top|right|bottom|left)$/,
@@ -47,7 +47,7 @@ function isHidden( elem, el ) {
 	// isHidden might be called from jQuery#filter function;
 	// in that case, element will be second argument
 	elem = el || elem;
-	return curCSS( elem, "display" ) === "none" || !jQuery.contains( elem.ownerDocument, elem );
+	return jQuery.css( elem, "display" ) === "none" || !jQuery.contains( elem.ownerDocument, elem );
 }
 
 function showHide( elements, show ) {
@@ -76,7 +76,7 @@ function showHide( elements, show ) {
 				values[ index ] = jQuery._data( elem, "olddisplay", css_defaultDisplay(elem.nodeName) );
 			}
 		} else if ( !values[ index ] && !isHidden( elem ) ) {
-			jQuery._data( elem, "olddisplay", curCSS( elem, "display" ) );
+			jQuery._data( elem, "olddisplay", jQuery.css( elem, "display" ) );
 		}
 	}
 
@@ -217,7 +217,7 @@ jQuery.extend({
 		}
 	},
 
-	css: function( elem, name, numeric, extra ) {
+	css: function( elem, name, extra, styles ) {
 		var val, num, hooks,
 			origName = jQuery.camelCase( name );
 
@@ -235,7 +235,7 @@ jQuery.extend({
 
 		// Otherwise, if a way to get the computed value exists, use that
 		if ( val === undefined ) {
-			val = curCSS( elem, name );
+			val = curCSS( elem, name, styles );
 		}
 
 		//convert "normal" to computed value
@@ -244,9 +244,9 @@ jQuery.extend({
 		}
 
 		// Return, converting to number if forced or a qualifier was provided and val looks numeric
-		if ( numeric || extra !== undefined ) {
+		if ( extra ) {
 			num = parseFloat( val );
-			return numeric || jQuery.isNumeric( num ) ? num || 0 : val;
+			return extra === true || jQuery.isNumeric( num ) ? num || 0 : val;
 		}
 		return val;
 	},
@@ -273,18 +273,22 @@ jQuery.extend({
 	}
 });
 
-// NOTE: To any future maintainer, we've window.getComputedStyle
+// NOTE: we've included the "window" in window.getComputedStyle
 // because jsdom on node.js will break without it.
 if ( window.getComputedStyle ) {
-	curCSS = function( elem, name ) {
-		var ret, width, minWidth, maxWidth,
-			computed = window.getComputedStyle( elem, null ),
-			style = elem.style;
+	getStyles = function( elem ) {
+		return window.getComputedStyle( elem, null );
+	};
 
-		if ( computed ) {
+	curCSS = function( elem, name, _computed ) {
+		var width, minWidth, maxWidth,
+			computed = _computed || getStyles( elem ),
 
 			// getPropertyValue is only needed for .css('filter') in IE9, see #12537
-			ret = computed.getPropertyValue( name ) || computed[ name ];
+			ret = computed ? computed.getPropertyValue( name ) || computed[ name ] : undefined,
+			style = elem.style;
+
+		if ( computed ) {
 
 			if ( ret === "" && !jQuery.contains( elem.ownerDocument, elem ) ) {
 				ret = jQuery.style( elem, name );
@@ -295,13 +299,17 @@ if ( window.getComputedStyle ) {
 			// Safari 5.1.7 (at least) returns percentage for a larger set of values, but width seems to be reliably pixels
 			// this is against the CSSOM draft spec: http://dev.w3.org/csswg/cssom/#resolved-values
 			if ( rnumnonpx.test( ret ) && rmargin.test( name ) ) {
+
+				// Remember the original values
 				width = style.width;
 				minWidth = style.minWidth;
 				maxWidth = style.maxWidth;
 
+				// Put in the new values to get a computed value out
 				style.minWidth = style.maxWidth = style.width = ret;
 				ret = computed.width;
 
+				// Revert the changed values
 				style.width = width;
 				style.minWidth = minWidth;
 				style.maxWidth = maxWidth;
@@ -311,9 +319,14 @@ if ( window.getComputedStyle ) {
 		return ret;
 	};
 } else if ( document.documentElement.currentStyle ) {
-	curCSS = function( elem, name ) {
-		var left, rsLeft,
-			ret = elem.currentStyle && elem.currentStyle[ name ],
+	getStyles = function( elem ) {
+		return elem.currentStyle;
+	};
+
+	curCSS = function( elem, name, _computed ) {
+		var left, rs, rsLeft,
+			computed = _computed || getStyles( elem ),
+			ret = computed ? computed[ name ] : undefined,
 			style = elem.style;
 
 		// Avoid setting ret to empty string here
@@ -333,11 +346,12 @@ if ( window.getComputedStyle ) {
 
 			// Remember the original values
 			left = style.left;
-			rsLeft = elem.runtimeStyle && elem.runtimeStyle.left;
+			rs = elem.runtimeStyle;
+			rsLeft = rs && rs.left;
 
 			// Put in the new values to get a computed value out
 			if ( rsLeft ) {
-				elem.runtimeStyle.left = elem.currentStyle.left;
+				rs.left = elem.currentStyle.left;
 			}
 			style.left = name === "fontSize" ? "1em" : ret;
 			ret = style.pixelLeft + "px";
@@ -345,7 +359,7 @@ if ( window.getComputedStyle ) {
 			// Revert the changed values
 			style.left = left;
 			if ( rsLeft ) {
-				elem.runtimeStyle.left = rsLeft;
+				rs.left = rsLeft;
 			}
 		}
 
@@ -360,7 +374,7 @@ function setPositiveNumber( elem, value, subtract ) {
 			value;
 }
 
-function augmentWidthOrHeight( elem, name, extra, isBorderBox ) {
+function augmentWidthOrHeight( elem, name, extra, isBorderBox, styles ) {
 	var i = extra === ( isBorderBox ? "border" : "content" ) ?
 		// If we already have the right measurement, avoid augmentation
 		4 :
@@ -372,29 +386,26 @@ function augmentWidthOrHeight( elem, name, extra, isBorderBox ) {
 	for ( ; i < 4; i += 2 ) {
 		// both box models exclude margin, so add it if we want it
 		if ( extra === "margin" ) {
-			// we use jQuery.css instead of curCSS here
-			// because of the reliableMarginRight CSS hook!
-			val += jQuery.css( elem, extra + cssExpand[ i ], true );
+			val += jQuery.css( elem, extra + cssExpand[ i ], true, styles );
 		}
 
-		// From this point on we use curCSS for maximum performance (relevant in animations)
 		if ( isBorderBox ) {
 			// border-box includes padding, so remove it if we want content
 			if ( extra === "content" ) {
-				val -= parseFloat( curCSS( elem, "padding" + cssExpand[ i ] ) ) || 0;
+				val -= jQuery.css( elem, "padding" + cssExpand[ i ], true, styles );
 			}
 
 			// at this point, extra isn't border nor margin, so remove border
 			if ( extra !== "margin" ) {
-				val -= parseFloat( curCSS( elem, "border" + cssExpand[ i ] + "Width" ) ) || 0;
+				val -= jQuery.css( elem, "border" + cssExpand[ i ] + "Width", true, styles );
 			}
 		} else {
 			// at this point, extra isn't content, so add padding
-			val += parseFloat( curCSS( elem, "padding" + cssExpand[ i ] ) ) || 0;
+			val += jQuery.css( elem, "padding" + cssExpand[ i ], true, styles );
 
 			// at this point, extra isn't content nor padding, so add border
 			if ( extra !== "padding" ) {
-				val += parseFloat( curCSS( elem, "border" + cssExpand[ i ] + "Width" ) ) || 0;
+				val += jQuery.css( elem, "border" + cssExpand[ i ] + "Width", true, styles );
 			}
 		}
 	}
@@ -407,14 +418,15 @@ function getWidthOrHeight( elem, name, extra ) {
 	// Start with offset property, which is equivalent to the border-box value
 	var val = name === "width" ? elem.offsetWidth : elem.offsetHeight,
 		valueIsBorderBox = true,
-		isBorderBox = jQuery.support.boxSizing && jQuery.css( elem, "boxSizing" ) === "border-box";
+		styles = getStyles( elem ),
+		isBorderBox = jQuery.support.boxSizing && jQuery.css( elem, "boxSizing", false, styles ) === "border-box";
 
 	// some non-html elements return undefined for offsetWidth, so check for null/undefined
 	// svg - https://bugzilla.mozilla.org/show_bug.cgi?id=649285
 	// MathML - https://bugzilla.mozilla.org/show_bug.cgi?id=491668
 	if ( val <= 0 || val == null ) {
 		// Fall back to computed then uncomputed css if necessary
-		val = curCSS( elem, name );
+		val = curCSS( elem, name, styles );
 		if ( val < 0 || val == null ) {
 			val = elem.style[ name ];
 		}
@@ -438,7 +450,8 @@ function getWidthOrHeight( elem, name, extra ) {
 			elem,
 			name,
 			extra || ( isBorderBox ? "border" : "content" ),
-			valueIsBorderBox
+			valueIsBorderBox,
+			styles
 		)
 	) + "px";
 }
@@ -479,7 +492,7 @@ function css_defaultDisplay( nodeName ) {
 function actualDisplay( name, doc ) {
 	var elem, display;
 	elem = jQuery( doc.createElement( name ) );
-	display = curCSS( elem.appendTo( doc.body )[0], "display" );
+	display = jQuery.css( elem.appendTo( doc.body )[0], "display" );
 	elem.remove();
 	return display;
 }
@@ -490,7 +503,7 @@ jQuery.each([ "height", "width" ], function( i, name ) {
 			if ( computed ) {
 				// certain elements can have dimension info if we invisibly show them
 				// however, it must have a current display style that would benefit from this
-				if ( elem.offsetWidth === 0 && rdisplayswap.test( curCSS( elem, "display" ) ) ) {
+				if ( elem.offsetWidth === 0 && rdisplayswap.test( jQuery.css( elem, "display" ) ) ) {
 					return jQuery.swap( elem, cssShow, function() {
 						return getWidthOrHeight( elem, name, extra );
 					});
@@ -501,12 +514,14 @@ jQuery.each([ "height", "width" ], function( i, name ) {
 		},
 
 		set: function( elem, value, extra ) {
+			var styles = extra && getStyles( elem );
 			return setPositiveNumber( elem, value, extra ?
 				augmentWidthOrHeight(
 					elem,
 					name,
 					extra,
-					jQuery.support.boxSizing && jQuery.css( elem, "boxSizing" ) === "border-box"
+					jQuery.support.boxSizing && jQuery.css( elem, "boxSizing", false, styles ) === "border-box",
+					styles
 				) : 0
 			);
 		}
@@ -604,7 +619,7 @@ jQuery(function() {
 
 if ( jQuery.expr && jQuery.expr.filters ) {
 	jQuery.expr.filters.hidden = function( elem ) {
-		return ( elem.offsetWidth === 0 && elem.offsetHeight === 0 ) || (!jQuery.support.reliableHiddenOffsets && ((elem.style && elem.style.display) || curCSS( elem, "display" )) === "none");
+		return ( elem.offsetWidth === 0 && elem.offsetHeight === 0 ) || (!jQuery.support.reliableHiddenOffsets && ((elem.style && elem.style.display) || jQuery.css( elem, "display" )) === "none");
 	};
 
 	jQuery.expr.filters.visible = function( elem ) {

src/dimensions.js

@@ -31,7 +31,7 @@ jQuery.each( { Height: "height", Width: "width" }, function( name, type ) {
 
 				return value === undefined ?
 					// Get width or height on the element, requesting but not forcing parseFloat
-					jQuery.css( elem, type, value, extra ) :
+					jQuery.css( elem, type, extra ) :
 
 					// Set width or height on the element
 					jQuery.style( elem, type, value, extra );

src/effects.js

@@ -420,11 +420,11 @@ Tween.propHooks = {
 				return tween.elem[ tween.prop ];
 			}
 
-			// passing any value as a 4th parameter to .css will automatically
+			// passing a non empty string as a 3rd parameter to .css will automatically
 			// attempt a parseFloat and fallback to a string if the parse fails
 			// so, simple values such as "10px" are parsed to Float.
 			// complex values such as "rotate(1rad)" are returned as is.
-			result = jQuery.css( tween.elem, tween.prop, false, "" );
+			result = jQuery.css( tween.elem, tween.prop, "auto" );
 			// Empty strings, null, undefined and "auto" are converted to 0.
 			return !result || result === "auto" ? 0 : result;
 		},

src/offset.js

@@ -108,16 +108,16 @@ jQuery.fn.extend({
 			}
 
 			// Add offsetParent borders
-			parentOffset.top  += parseFloat( jQuery.css( offsetParent[ 0 ], "borderTopWidth" ) ) || 0;
-			parentOffset.left += parseFloat( jQuery.css( offsetParent[ 0 ], "borderLeftWidth" ) ) || 0;
+			parentOffset.top  += jQuery.css( offsetParent[ 0 ], "borderTopWidth", true );
+			parentOffset.left += jQuery.css( offsetParent[ 0 ], "borderLeftWidth", true );
 		}
 
 		// Subtract parent offsets and element margins
 		// note: when an element has margin: auto the offsetLeft and marginLeft
 		// are the same in Safari causing offset.left to incorrectly be 0
 		return {
-			top:  offset.top  - parentOffset.top - ( parseFloat( jQuery.css( elem, "marginTop" ) ) || 0 ),
-			left: offset.left - parentOffset.left - ( parseFloat( jQuery.css( elem, "marginLeft" ) ) || 0 )
+			top:  offset.top  - parentOffset.top - jQuery.css( elem, "marginTop", true ),
+			left: offset.left - parentOffset.left - jQuery.css( elem, "marginLeft", true)
 		};
 	},