使用显示时如何显示Div：无

Question

I have hidden a <div> based on a response from an ajax method using display: none . 我已经使用display: none基于ajax方法的响应隐藏了<div> 。 What if I want to show the same <div> upon another call to the AJAX method? 如果我想在再次调用AJAX方法时显示相同的<div> ，该怎么办？

I am wondering if display: none actually removes the element from DOM because using display: block doesn't make the <div> visible again. 我想知道display: none实际上display: none从DOM中删除该元素，因为使用display: block不会使<div>再次可见。 How do I show and hide the same div using the display attribute. 如何使用display属性显示和隐藏相同的div。 Here's the code I am using for the AJAX call: 这是我用于AJAX调用的代码：

$.ajax({
  type: "POST",
  url: "Request.aspx/FireEvents",
  data: JSON.stringify({ controlValues: pageControlNamesAndValues }),
  contentType: "application/json; charset=utf-8",
  dataType: "json",
  success: function (response) {
    var controlVals = response.d;
    $.each(controlVals, function (index, currentControl) {
      var targetDropDown = document.getElementById(ctrlName);
      console.log('Targetdropdown is ' + targetDropDown);
      if (targetDropDown != null) {
        if (targetDropDown instanceof HTMLDivElement) {
          if (currentControl.ControlName == "LogicChecks") {
            if (currentControl.ControlValue = "hidden") {
              targetDropDown.style.display = 'none';
            } else {
              targetDropDown.style.display = 'block';
            }
          }
        }
      }
    });
  }
});

The last line ( ...style.display ='block'; ) doesn't show the <div> once it has been hidden. 隐藏<div>后，最后一行（ ...style.display ='block'; ）不会显示它。

Answer 1

Use jQuery to show and hide: 使用jQuery显示和隐藏：

$("#"+ ctrlName).show() 
$("#"+ ctrlName).hide()

Also use == to test for equality; 也使用==来测试是否相等； = is assignment This statement is not testing for hidden but assigning hidden =是赋值此语句不是测试隐藏的，而是分配隐藏的

if(currentControl.ControlValue="hidden")

Lastly 最后

var targetDropDown = document.getElementById(ctrlName); 
if (targetDropDown == null) { targetDropDown = 
  document.getElementById(ctrlName); }

does not make logical sense 不合逻辑

Perhaps this is what you mean 也许这就是你的意思

function ProcessEventsActions(pageControlNamesAndValues) {
  $.ajax({
      type: "POST",
      url: "Request.aspx/FireEvents",
      data: JSON.stringify({
        controlValues: pageControlNamesAndValues
      }),
      contentType: "application/json; charset=utf-8",
      dataType: "json",
      success: function(response) {
        var controlVals = response.d;
        $.each(controlVals, function(index, currentControl) {
          if (currentControl.ControlName == "LogicChecks") {
            targetDropDown = $("#" + currentControl.controlDiv); // or whatever the name is
            targetDropdown.toggle(currentControl.ControlValue != "hidden"); // show if not hidden
          }
        });
      });
  });
}

Answer 2

As discussed in the comments and demonstrated in Matt's answer, the method for showing / hiding elements is correct, that is 正如评论中所讨论并在Matt的答案中所演示的那样，显示/隐藏元素的方法是正确的，即

element.style.display = "block";

Behaves as you would expect, even after it has been hidden by applying display: none . 即使通过应用display: none隐藏了它，也仍会表现出预期的效果display: none 。 Here is an example using jQuery instead (since this is a jQuery question): 这是一个使用jQuery的示例（因为这是一个jQuery问题）：

 $("#click1").click(function() { $("#el").hide(); }); $("#click2").click(function() { $("#el").show(); });

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <div id="el">Visible</div> <button id="click1">Click to hide</button> <button id="click2">Click to show</button>

The problem is definitely with the rest of your code. 问题肯定出在其余的代码上。 A likely suspect is this line: 这行可能是可疑的：

if (currentControl.ControlValue = "hidden") {

If you indeed copied your code directly and this is not a typo, this condition will always evaluate to true / a truthy value! 如果您确实直接复制了代码并且这不是错字，则此条件将始终评估为true /真实值！ And this would cause the problems you are describing, since the code would always hide the element, never showing it again. 这将导致您正在描述的问题，因为代码将始终隐藏该元素，而不再显示它。 To fix this, simply replace the line with: 要解决此问题，只需将行替换为：

if (currentControl.ControlValue == "hidden") {

Answer 3

Here is an example of it working. 这是它工作的一个例子。 Make sure you are accessing the element correctly. 确保您正确访问元素。

 <!DOCTYPE html> <html> <head> <style> #myDIV { width: 500px; height: 500px; background-color: lightblue; display:none; } </style> </head> <body> <p>Click the "Try it" button to set the display property of the DIV element to "block":</p> <button onclick="myFunction()">Try it</button> <div id="myDIV"> This is my DIV element. </div> <p><b>Note:</b> The element will not take up any space when the display property set to "none".</p> <script> function myFunction() { document.getElementById("myDIV").style.display = "block"; } </script> </body> </html>

使用显示时如何显示Div：无

问题描述

3 个解决方案

解决方案1
1 已采纳 2017-07-17 18:12:57

解决方案2
1 2017-07-17 18:18:08

解决方案3
0 2017-07-17 18:06:44

使用显示时如何显示Div：无

问题描述

3 个解决方案

解决方案1 1 已采纳 2017-07-17 18:12:57

解决方案2 1 2017-07-17 18:18:08

解决方案3 0 2017-07-17 18:06:44

解决方案1
1 已采纳 2017-07-17 18:12:57

解决方案2
1 2017-07-17 18:18:08

解决方案3
0 2017-07-17 18:06:44