4564 jQuery.fn.css = function( name, value ) {

4565 return access( this, name, value, true, function( elem, name, value ) {

4566 if ( value === undefined ) {

4567 return jQuery.curCSS( elem, name );

4568 }

4569

4570 if ( typeof value === "number" && !rexclude.test(name) ) {

4571 value += "px";

4572 }

4573

4574 jQuery.style( elem, name, value );

4575 });

4576 };

if value is NaN, typeof value === "number" && !rexclude.test(name) returns true, and so "NaNpx" will be passed to jQuery.style, which causes error.

This occur frequently, because we cannot guarantee value is never NaN. One example is: ele.css('right',parseInt(anotherEle.css('right')))

where anotherEle.css('right') is 'auto'

IMO, isNaN(value) should be added.