在实际开发中会遇到确实需要获取隐藏元素的宽高，这儿所说的隐藏元素是display为none的元素。
可使用jQuery Actual Plugin插件来完成，其源码如下：
;( function ( $ ){ $.fn.addBack = $.fn.addBack || $.fn.andSelf; $.fn.extend({ actual : function ( method, options ){ // check if the jQuery method exist if( !this[ method ]){ throw '$.actual => The jQuery method "' + method + '" you called does not exist'; } var defaults = { absolute : false, clone : false, includeMargin : false, display : 'block' }; var configs = $.extend( defaults, options ); var $target = this.eq( 0 ); var fix, restore; if( configs.clone === true ){ fix = function (){ var style = 'position: absolute !important; top: -1000 !important; '; // this is useful with css3pie $target = $target. clone(). attr( 'style', style ). appendTo( 'body' ); }; restore = function (){ // remove DOM element after getting the width $target.remove(); }; }else{ var tmp = []; var style = ''; var $hidden; fix = function (){ // get all hidden parents $hidden = $target.parents().addBack().filter( ':hidden' ); style += 'visibility: hidden !important; display: ' + configs.display + ' !important; '; if( configs.absolute === true ) style += 'position: absolute !important; '; // save the origin style props // set the hidden el css to be got the actual value later $hidden.each( function (){ // Save original style. If no style was set, attr() returns undefined var $this = $( this ); var thisStyle = $this.attr( 'style' ); tmp.push( thisStyle ); // Retain as much of the original style as possible, if there is one $this.attr( 'style', thisStyle ? thisStyle + ';' + style : style ); }); }; restore = function (){ // restore origin style values $hidden.each( function ( i ){ var $this = $( this ); var _tmp = tmp[ i ]; if( _tmp === undefined ){ $this.removeAttr( 'style' ); }else{ $this.attr( 'style', _tmp ); } }); }; } fix(); // get the actual value with user specific methed // it can be 'width', 'height', 'outerWidth', 'innerWidth'... etc // configs.includeMargin only works for 'outerWidth' and 'outerHeight' var actual = /(outer)/.test( method ) ? $target[ method ]( configs.includeMargin ) : $target[ method ](); restore(); // IMPORTANT, this plugin only return the value of the first element return actual; } }); })(jQuery);
当然如果要支持模块化开发，直接使用官网下载的文件即可，源码也贴上：
;( function ( factory ) { if ( typeof define === 'function' && define.amd ) { // AMD. Register module depending on jQuery using requirejs define. define( ['jquery'], factory ); } else { // No AMD. factory( jQuery ); } }( function ( $ ){ $.fn.addBack = $.fn.addBack || $.fn.andSelf; $.fn.extend({ actual : function ( method, options ){ // check if the jQuery method exist if( !this[ method ]){ throw '$.actual => The jQuery method "' + method + '" you called does not exist'; } var defaults = { absolute : false, clone : false, includeMargin : false, display : 'block' }; var configs = $.extend( defaults, options ); var $target = this.eq( 0 ); var fix, restore; if( configs.clone === true ){ fix = function (){ var style = 'position: absolute !important; top: -1000 !important; '; // this is useful with css3pie $target = $target. clone(). attr( 'style', style ). appendTo( 'body' ); }; restore = function (){ // remove DOM element after getting the width $target.remove(); }; }else{ var tmp = []; var style = ''; var $hidden; fix = function (){ // get all hidden parents $hidden = $target.parents().addBack().filter( ':hidden' ); style += 'visibility: hidden !important; display: ' + configs.display + ' !important; '; if( configs.absolute === true ) style += 'position: absolute !important; '; // save the origin style props // set the hidden el css to be got the actual value later $hidden.each( function (){ // Save original style. If no style was set, attr() returns undefined var $this = $( this ); var thisStyle = $this.attr( 'style' ); tmp.push( thisStyle ); // Retain as much of the original style as possible, if there is one $this.attr( 'style', thisStyle ? thisStyle + ';' + style : style ); }); }; restore = function (){ // restore origin style values $hidden.each( function ( i ){ var $this = $( this ); var _tmp = tmp[ i ]; if( _tmp === undefined ){ $this.removeAttr( 'style' ); }else{ $this.attr( 'style', _tmp ); } }); }; } fix(); // get the actual value with user specific methed // it can be 'width', 'height', 'outerWidth', 'innerWidth'... etc // configs.includeMargin only works for 'outerWidth' and 'outerHeight' var actual = /(outer)/.test( method ) ? $target[ method ]( configs.includeMargin ) : $target[ method ](); restore(); // IMPORTANT, this plugin only return the value of the first element return actual; } }); }));
代码实例：
//get hidden element actual width $('.hidden').actual('width'); //get hidden element actual innerWidth $('.hidden').actual('innerWidth'); //get hidden element actual outerWidth $('.hidden').actual('outerWidth'); //get hidden element actual outerWidth and set the `includeMargin` argument $('.hidden').actual('outerWidth',{includeMargin:true}); //get hidden element actual height $('.hidden').actual('height'); //get hidden element actual innerHeight $('.hidden').actual('innerHeight'); //get hidden element actual outerHeight $('.hidden').actual('outerHeight'); // get hidden element actual outerHeight and set the `includeMargin` argument $('.hidden').actual('outerHeight',{includeMargin:true}); //if the page jumps or blinks, pass a attribute '{ absolute : true }' //be very careful, you might get a wrong result depends on how you makrup your html and css $('.hidden').actual('height',{absolute:true}); // if you use css3pie with a float element // for example a rounded corner navigation menu you can also try to pass a attribute '{ clone : true }' // please see demo/css3pie in action $('.hidden').actual('width',{clone:true});