得到元素真实的背景颜色的js代码_javascript技巧

<title>得到元素真实的背景颜色</title> <style> .classname {background-color:#ff99dd;} #div3 {background-color:#d8bfd8;} div {background-color:#87cefa;border:1px solid #333333;margin:10px;padding:4px;} body {background-color:#bed742;} #div4 {background-color:transparent;} </style> <span style="text-align:center;font-size:20px;color:#ff7f50;width:100%;">得到元素真实的背景颜色 <font style="font-size:12px;">By <a href="http://longbill.cn" target="_blank">Longbill</a></font></span> <div id="div1">div1 直接通过div标签定义背景色(#87cefa)</div> <div id="div2" class="classname">div2 通过class name定义背景色(#ff99dd)</div> <div id="div3">div3 通过id定义背景色(#d8bfd8)</div> <div id="div4">div4 这是一个透明的div，背景色应为上一个元素的颜色(#bed742)</div> <button onclick="go()">getBg()</button> <script> function getBg(element) {//author: Longbill (www.longbill.cn) //dnew.cn修补 var rgbToHex=function(rgbarray,array){ if (rgbarray.length < 3) return false; if (rgbarray.length == 4 && rgbarray[3] == 0 && !array) return 'transparent'; var hex = []; for (var i = 0; i < 3; i++){ var bit = (rgbarray[i] - 0).toString(16); hex.push((bit.length == 1) ? '0' + bit : bit); } return array ? hex : '#' + hex.join(''); } //--------------- if (typeof element == "string") element = document.getElementById(element); if (!element) return; cssProperty = "backgroundColor"; mozillaEquivalentCSS = "background-color"; if (element.currentStyle) var actualColor = element.currentStyle[cssProperty]; else { var cs = document.defaultView.getComputedStyle(element, null); var actualColor = cs.getPropertyValue(mozillaEquivalentCSS).match(/\d{1,3}/g); //----- actualColor = (actualColor) ? rgbToHex(actualColor) : "transparent"; } if (actualColor == "transparent" && element.parentNode) return arguments.callee(element.parentNode); if (actualColor == null) return "#ffffff"; else return actualColor; } function go() { for(var i=1;i<=4;i++) eval("alert('div"+i+":'+getBg('div"+i+"'));"); } </script>
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