jquery $(window).width() 和 $(window).height() 在未调整视口大小时返回不同的值

我正在使用jquery编写一个站点，它反复调用$(window).width()和$(window).height()来根据视口大小定位和调整元素的大小.

In troubleshooting I discovered that I am getting slightly different viewport size reports in repeated calls to the above jquery functions when the viewport is not resized.

想知道是否有任何特殊情况下，任何人都知道这种情况发生，或者如果这只是它的方式.据报道，大小的差异似乎是20px或更小.它发生在Mac OS X 10.6.2上的Safari 4.0.4、Firefox 3.6.2和Chrome 5.0.342.7测试版中.我还没有测试其他浏览器，因为它似乎不是特定于浏览器的.我也无法找出差异取决于什么，如果不是视口大小，是否还有其他因素导致结果不同？

如有任何见解，将不胜感激.

update:

It is not the values of $(window).width() and $(window).height() that are changing. It's the values of the variables I am using to store the values of the above.

影响值的不是滚动条，当变量值更改时不会出现滚动条.下面是我在变量中存储值的代码(我这样做只是为了让它们更短).

(这一切都在$(document).ready()以内)

//initially declare the variables to be visible to otehr functions within .ready()

var windowWidth = $(window).width(); //retrieve current window width
var windowHeight = $(window).height(); //retrieve current window height
var documentWidth = $(document).width(); //retrieve current document width
var documentHeight = $(document).height(); //retrieve current document height
var vScrollPosition = $(document).scrollTop(); //retrieve the document scroll ToP position
var hScrollPosition = $(document).scrollLeft(); //retrieve the document scroll Left position


function onm_window_parameters(){ //called on viewer reload, screen resize or scroll

    windowWidth = $(window).width(); //retrieve current window width
    windowHeight = $(window).height(); //retrieve current window height
    documentWidth = $(document).width(); //retrieve current document width
    documentHeight = $(document).height(); //retrieve current document height
    vScrollPosition = $(document).scrollTop(); //retrieve the document scroll ToP position
    hScrollPosition = $(document).scrollLeft(); //retrieve the document scroll Left position

}; //end function onm_window_parameters()

I inserted an alert statement to probe the variables above against the values they are supposed to be holding. The $(item).param() values stay consistent, but my variables change for reasons I can't figure out.

我一直在寻找我的代码可能会改变相关变量值的地方，而不是仅仅检索它们的设置值，却什么都找不到.如果有可能的话，我可以把整个shebang发到某个地方.