jQuery选择器（三）

子元素过滤选择器：

l  nth-child() 选择器详解如下：

•    (1) :nth-child(even/odd): 能选取每个父元素下的索引值为偶(奇)数的元素

•    (2):nth-child(2): 能选取每个父元素下的索引值为2 的元素

•    (3):nth-child(3n): 能选取每个父元素下的索引值是3 的倍数的元素

•    (3):nth-child(3n + 1): 能选取每个父元素下的索引值是 3n + 1的元素

<ul>

            <li>

                Jone

            </li>

            <li>

                Karl

            </li>

            <li>

                Brandon

            </li>

        </ul>

        <ul>

            <li>

                Glen

            </li>

            <li>

                Tane

            </li>

            <li>

                Ralph

            </li>

        </ul>

 

$("ul>li:nth-child(even").css("background-color","red");

       $("ul>li:first-child").css("background-color","blue");

       $("ul>li:last-child").css("background-color","red");

    $("ul>li:only-child").css("background-color","green");

 

表单对象过滤器：

此选择器主要对所选择的表单元素进行过滤

<divalign="center">

                            <form>

                                     <inputtype="button" value="Input Button" /><br/>

                                     <inputtype="checkbox" /><br/>

 

                                     <inputtype="file" /><br/>

                                     <inputtype="hidden" /><br/>

                                     <inputtype="image" src="./images/IMAG0186.jpg"width="50px" height="50px"/><br/>

 

                                     <inputtype="password" /><br/>

                                     <inputtype="radio" /><br/>

                                     <inputtype="reset" /><br/>

 

                                     <inputtype="submit" /><br/>

                                     <inputtype="text" /><br/>

                                     <select>

                                               <option>

                                                        Option

                                               </option>

                                     </select><br/>

 

                                     <textarea></textarea><br/>

                                     <button>

                                               Button

                                     </button>

 

                            </form>

                            <divid="ts">

                                       <inputtype="password" /><br/>

                            </div>

                   </div>

 

  $(document).ready(function(){

           // 表单 过滤器匹配所有 input, textarea, select 和 button 元素

            var $ipts = $(":input");

            //alert($ipts.length);

            //alert($(":text").length);

            

            alert($("input:text").length);// input : text

   });

 

前提：引入js文件