Question

我正在开发一个首先创建了许多选择表单的网页。当用户为特定选择表单选择选项时，将根据用户选择创建另一个子表单，并将其附加到该选择表单。不幸地，我的代码不起作用，例如，（1）没有创建子表单，（2）用于附加子表单的选择器没有正确编码 - 它们总是指向固定值（#wrapper-options3）。我的原始代码更复杂，但我在下面的代码中复制了结构+一些简单的示例函数 - 它导致与原始代码相同的错误。我应该如何正确编码子表单的添加（在下面的代码中的步骤2中）？例如，如何为＃wrapper-options获得正确的选择器值？

    <script>
    $(document).ready(function(){ 
        var previous;

        //functions
        var Buildform = function(i){
            var form;
            form = '<select class="eprodtype'+i+'" name="transport'+i+'">';
            form += '<option value="bike"> Bike'+i+' </option>';
            form += '<option value="car"> Car'+i+' </option>';
            form += '</select>';
            form += '<div id="wrapper-options'+i+'"> "wrapper-options'+i+'" </div>';
            return $(form);
        }//Buildform

        var Buildsubform = function(i){ //i will contain <select> value 
           var subform = '<p> '+i+' </p>';
           console.log('Buildsubform():'+subform);
           return $(subform);
        }

        //step 1: build 'base' form with multiple select forms
        for(var i=0;i<3;i++){
            var form = Buildform(i);
            $('#wrapper').append(form);

        }

        //step 2: build subform depending on choice user within base form
        for(var i=0;i<3;i++){
          $(".eprodtype"+i).focus(function () {
            // Store the current value on focus and on change
            var previous = this.value; //old select value
          }).change(function() {

          var subform = Buildsubform(this.value);
          console.log('append subform'+subform);
          //ERROR IN THE NEXT 2 LINES; selector '#wrapper-options'+i always has a value #wrapper-options3 - instead of a dynamic value
          $('#wrapper-options'+i).html(''); //remove previous subform
          $('#wrapper-options'+i).html(subform);
          var str = '#wrapper-options'+i;
          console.log('wrapper-options val: '+str);
          console.log('change eprod val: '+this.value);

          previous = this.value;
       });
        }//for i

    }); //$(document).ready  
    </script>
</head>
<body>
    <form>
      <div id="wrapper"></div> <!--wrapper for function Buildform() -->
    </form>
</body>

Answer 1

.change()函数的范围与自事件触发事件时包装它的代码不同，而不是内联。所以当它运行时，它不知道值i是什么。您需要传递一个值来获取正确的引用，否则它将始终是自包装代码完成执行以来的最后一个i值。

此外，您可能希望查看使用相对选择器并取消对元素进行编号。

Answer 2

试试这个并查看delegate以供参考。

<script>
    $(document).ready(function(){ 
        var previous;

        //functions
        var Buildform = function(i){
            var form;
            form = '<form><select class="eprodtype'+i+'" name="transport'+i+'">';
            form += '<option value="bike"> Bike'+i+' </option>';
            form += '<option value="car"> Car'+i+' </option>';
            form += '</select>';
            form += '<div id="wrapper-options'+i+'"> "wrapper-options'+i+'" </div></form>';
            return form;
        }//Buildform

        var Buildsubform = function(i){ //i will contain <select> value 
           var subform = '<p> '+i+' </p>';
           console.log('Buildsubform():'+subform);
           return subform;
        }

        //step 1: build 'base' form with multiple select forms
        for(var i=0;i<3;i++){
            var form = Buildform(i);
            $('#wrapper').append(form);

        }

        //step 2: build subform depending on choice user within base form
        for(var i=0;i<3;i++){
            $('body').on('focus', ".eprodtype"+i, function () {
            // Store the current value on focus and on change
            var previous = this.value; //old select value
          }).on('change', ".eprodtype"+i, function() {

          var subform = Buildsubform(this.value);
          console.log('append subform'+subform);
          //ERROR IN THE NEXT 2 LINES; selector '#wrapper-options'+i always has a value #wrapper-options3 - instead of a dynamic value
          $('#wrapper-options'+i).html(''); //remove previous subform
          $('#wrapper-options'+i).html(subform);
          var str = '#wrapper-options'+i;
          console.log('wrapper-options val: '+str);
          console.log('change eprod val: '+this.value);

          previous = this.value;
       });
        }//for i

    }); //$(document).ready  
    </script>
</head>
<body>
    <form>
      <div id="wrapper"></div> <!--wrapper for function Buildform() -->
    </form>
</body>

动态创建的网页不起作用

2 个答案: