jquery 的冷知识，自定义选择器。
代码如下：
// HTML 代码 <body> <div id="divid1" class="divclass">白色</div> <div id="divid2" class="divclass">白色</div> <div id="divid3" class="divclass">白色</div> <div id="divid4" class="divclass">白色</div> <p style="500px;"> <input type="button" value="按钮[绿色]" id="but1" /> <input type="button" value="按钮[红色]" id="but2" /> <input type="button" value="按钮[蓝色]" id="but3" /> <input type="button" value="按钮[黄色]" id="but4" /> </p> <script type="text/javascript"> // 初始化自定义选择器 $(function () { $.expr[":"].greenbg = function (obj) { if (obj.style.backgroundColor === "green") return $(obj).css("background-color", "white"), $(obj).text("白色"); return $(obj).css("background-color", "green"), $(obj).text("绿色"); }; $.expr[":"].redbg = function (obj) { if (obj.style.backgroundColor == "red") return $(obj).css("background-color", "white"), $(obj).text("白色"); return $(obj).css("background-color", "red"), $(obj).text("红色"); }; $.expr[":"].blackbg = function (obj) { if (obj.style.backgroundColor == "blue") return $(obj).css("background-color", "white"), $(obj).text("白色"); return $(obj).css("background-color", "blue"), $(obj).text("红色"); }; $.expr[":"].yellowbg = function (obj) { if (obj.style.backgroundColor == "yellow") return $(obj).css("background-color", "white"), $(obj).text("白色"); return $(obj).css("background-color", "yellow"), $(obj).text("黄色"); }; }); // 使用自定义选择器 $("#but1").click(function () { $("#divid1:greenbg"); }); $("#but2").click(function () { $("#divid2:redbg"); }); $("#but3").click(function () { $("#divid3:blackbg"); }); $("#but4").click(function () { $("#divid4:yellowbg"); }); </script>