针对选择：

1.效果：

上边有三个按钮。下边有10个复选框：

点击第一个按钮，下边的复选框全选

点击第二个按钮，下边的复选框全部撤销

点击第三个按钮，反选（选中的会撤销，没有选中的会选中）；

代码：

                          var inp = document.getElementsByTagName("input");

                          var btn = document.getElementsByTagName("button");

 

                         btn[0].onclick = function(){

                         for(var i = 0;i<inp.length;i++){

                         inp[i].checked = true;

                          }

                         btn[1].onclick = function(){

                                for(var i = 0;i<inp.length;i++){

                                inp[i].checked = false;        

                                }

                          }

                         btn[2].onclick = function(){

                              for(var i = 0;i<inp.length;i++){

                                       if( inp[i].checked == true){

                                       inp[i].checked = false;

 

                              }else{

                              inp[i].checked = true;        

                             }

 

                      }

 

                }

       }

}

 

注解：inp是获取的10个input的id

            btn是获取的三个按钮的id

记住每一个都要用到for循环。