ccs3属性backgroundsize：覆盖机制

Question

我使用了背景：覆盖图像，它完美地完成了工作，但问题是如何获得图像尺寸，这对于任何屏幕尺寸都是如此。

我想计算得到图像渲染的高度和宽度，我有原始图像的高度和宽度，屏幕尺寸与我

Answer 1

var screenWidth = 1366; //width of screen or element need to show
var screenHeight = 768;//heightof screen or element need to show
var originalImageWidth = 800; // original image width
var originalImageHeight = 600; // original image height

var backgroundHeight,backgroundWidth;

//default scale by height of screen 
backgroundHeight = screenHeight ;
backgroundWidth= backgroundHeight * originalImageWidth / originalImageHeight;
if ((screenWidth - backgroundWidth) > 0) {//if width of scale images is smaller screen show, begin scale by width
    backgroundWidth = screenWidth;
    backgroundHeight = screenWidth * originalImageHeight / originalImageWidth;
}

然后使用css background-size percent

$(element).css({"background-size":(backgroundWidth+"px"+" "+backgroundHeight+"px")});