javascript 得到当前页面可视高度和宽度

function getHeight(){

var yScroll;

if (window.innerHeight && window.scrollMaxY) {

yScroll = window.innerHeight + window.scrollMaxY;

} else if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac

yScroll = document.body.scrollHeight;

} else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari

yScroll = document.body.offsetHeight;

}



var windowHeight;

if (self.innerHeight) { // all except Explorer

windowHeight = self.innerHeight;

} else if (document.documentElement && document.documentElement.clientHeight) {

// Explorer 6 Strict Mode

windowHeight = document.documentElement.clientHeight;

} else if (document.body) { // other Explorers

windowHeight = document.body.clientHeight;

}

// for small pages with total height less then height of the viewport

if(yScroll < windowHeight){

pageHeight = windowHeight;

} else {

pageHeight = yScroll;

}

return pageHeight;

}



function getWidth(){

var xScroll

if (window.innerHeight && window.scrollMaxY) {

xScroll = document.body.scrollWidth;

} else if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac

xScroll = document.body.scrollWidth;

} else {

xScroll = document.body.offsetWidth;

}

var windowWidth

if (self.innerHeight) { // all except Explorer

windowWidth = self.innerWidth;

} else if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode

windowWidth = document.documentElement.clientWidth;

} else if (document.body) { // other Explorers

windowWidth = document.body.clientWidth;

}

if(xScroll < windowWidth){

pageWidth = windowWidth;

} else {

pageWidth = xScroll;

}

return pageWidth;

}