diff --git a/src/css.js b/src/css.js
index b8a135005..f77497b4f 100644
--- a/src/css.js
+++ b/src/css.js
@@ -8,10 +8,6 @@ var exclude = /z-?index|font-?weight|opacity|zoom|line-?height/i,
 jQuery.fn.css = function( name, value ) {
 	var options = name, isFunction = jQuery.isFunction( value );
 
-	// ignore negative width and height values
-	if ( (name == 'width' || name == 'height') && parseFloat(value) < 0 )
-		value = undefined;
-
 	if ( typeof name === "string" ) {
 		// Are we setting the style?
 		if ( value === undefined ) {
@@ -55,6 +51,10 @@ jQuery.extend({
 		if (!elem || elem.nodeType == 3 || elem.nodeType == 8)
 			return undefined;
 
+		// ignore negative width and height values #1599
+		if ( (name == 'width' || name == 'height') && parseFloat(value) < 0 )
+			value = undefined;
+
 		var style = elem.style || elem, set = value !== undefined;
 
 		// IE uses filters for opacity
diff --git a/test/unit/css.js b/test/unit/css.js
index af1983cc1..a70b11534 100644
--- a/test/unit/css.js
+++ b/test/unit/css.js
@@ -1,7 +1,7 @@
 module("css");
 
 test("css(String|Hash)", function() {
-	expect(19);
+	expect(21);
 
 	equals( jQuery('#main').css("display"), 'none', 'Check for css property "display"');
 
@@ -11,6 +11,12 @@ test("css(String|Hash)", function() {
 	jQuery('#nothiddendiv').css({display: 'block'});
 	ok( jQuery('#nothiddendiv').is(':visible'), 'Modified CSS display: Assert element is visible');
 
+	// handle negative numbers by ignoring #1599, #4216
+	var width = parseFloat(jQuery('#nothiddendiv').css('width')), height = parseFloat(jQuery('#nothiddendiv').css('height'));
+	jQuery('#nothiddendiv').css({ width: -1, height: -1 });
+	equals( parseFloat(jQuery('#nothiddendiv').css('width')), width, 'Test negative width ignored')
+	equals( parseFloat(jQuery('#nothiddendiv').css('height')), height, 'Test negative height ignored')
+
 	jQuery('#floatTest').css({styleFloat: 'right'});
 	equals( jQuery('#floatTest').css('styleFloat'), 'right', 'Modified CSS float using "styleFloat": Assert float is right');
 	jQuery('#floatTest').css({cssFloat: 'left'});