<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Document</title> <style> body{background: RGB(222,222,2);} </style> </head> <body> <input type='button' value='點擊按鈕獲取頁面背景色' onclick="fun()"/> <script type="text/javascript"> /* ＊javascript的style屬性只能獲取內聯樣式，對於外部樣式和嵌入式樣式*需要用currentStyle屬性。但這種方法有兼容性（FF和Chrome不支持) */ HTMLElement.prototype.__defineGetter__("currentStyle", function() { return this.ownerDocument.defaultView.getComputedStyle(this, null); }); function fun(){ var color = document.body.currentStyle.backgroundColor; alert(color); } </script> </body> </html>