jQuery 获取屏幕高度、宽度

alert($(window).height()); //浏览器当前窗口可视区域高度 
alert($(document).height()); //浏览器当前窗口文档的高度 
alert($(document.body).height());//浏览器当前窗口文档body的高度 
alert($(document.body).outerHeight(true));//浏览器当前窗口文档body的总高度 包括border padding margin 
alert($(window).width()); //浏览器当前窗口可视区域宽度 
alert($(document).width());//浏览器当前窗口文档对象宽度 
alert($(document.body).width());//浏览器当前窗口文档body的高度 
alert($(document.body).outerWidth(true));//浏览器当前窗口文档body的总宽度 包括border padding margin 
 
// 获取页面的高度、宽度
function getPageSize() {
    var xScroll, yScroll;
    if (window.innerHeight && window.scrollMaxY) {
        xScroll = window.innerWidth + window.scrollMaxX;
        yScroll = window.innerHeight + window.scrollMaxY;
    } else {
        if (document.body.scrollHeight > document.body.offsetHeight) { // all but Explorer Mac    
            xScroll = document.body.scrollWidth;
            yScroll = document.body.scrollHeight;
        } else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari    
            xScroll = document.body.offsetWidth;
            yScroll = document.body.offsetHeight;
        }
    }
    var windowWidth, windowHeight;
    if (self.innerHeight) { // all except Explorer    
        if (document.documentElement.clientWidth) {
            windowWidth = document.documentElement.clientWidth;
        } else {
            windowWidth = self.innerWidth;
        }
        windowHeight = self.innerHeight;
    } else {
        if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode    
            windowWidth = document.documentElement.clientWidth;
            windowHeight = document.documentElement.clientHeight;
        } else {
            if (document.body) { // other Explorers    
                windowWidth = document.body.clientWidth;
                windowHeight = document.body.clientHeight;
            }
        }
    }       
    // for small pages with total height less then height of the viewport    
    if (yScroll < windowHeight) {
        pageHeight = windowHeight;
    } else {
        pageHeight = yScroll;
    }    
    // for small pages with total width less then width of the viewport    
    if (xScroll < windowWidth) {
        pageWidth = xScroll;
    } else {
        pageWidth = windowWidth;
    }
    arrayPageSize = new Array(pageWidth, pageHeight, windowWidth, windowHeight);
    return arrayPageSize;
}
 
// 滚动条
document.body.scrollTop;
$(document).scrollTop();