html – CSS伪元素input-placeholder :: after在文本框中显示有无值

我试图在验证后使用占位符伪元素(从文本框开始)为用户获取表格元素上的一些UI标记.我想要的是:: input-placeholder :: after伪元素,当文本框中既有值也有文本框中没有值时(例如,当存在无效值时)或者当需要一个值时 – 应该通过:: input-placeholder :: after伪元素在文本框的最右侧显示红色“X”.

这是小提琴：
https://jsfiddle.net/edsinek/L8u7s25d/

这是我用来显示无效值“X”的CSS片段：

.input-invalid input[type=text]::-webkit-input-placeholder::after {
  content: "\2716"; // "X"
  font-size: 18px;
  color: #ff0000;
  padding-right: 0;
  float: right;
}

注意：我目前只对Chrome进行编码,因此请原谅webkit特定的内容.

有任何想法吗？或者这是不可能的事情并且依赖于UA？

解决方法

原始答案:(在Chrome v47及更高版本中无效)

当您开始在文本框中键入内容时,:: – webkit-input-placeholder元素的可见性设置为隐藏.要显示其:: after元素,即使输入框有值,我们也需要覆盖它并将可见性设置为可见.

.input-invalid input[type=text]::-webkit-input-placeholder::after {
  visibility: visible;
}

var addFormFocusEventHandler = function() {
      var placeholder;
      // using the document Syntax in case input & container added to DOM dynamically
      $(document).on("focus","div.input-container :input",function() {
        $(this).closest("div.input-container").addClass("input-focused");
        placeholder = $(this).prop("placeholder");
        $(this).prop("placeholder"," ");
      }).on("blur",function() {
        $(this).closest("div.input-container").removeClass("input-focused");
        $(this).prop("placeholder",placeholder);
        placeholder = "";
      });
    };
    var addFormValueEventHandler = function() {
      // using the document Syntax in case input & container added to DOM dynamically
      $(document).on("blur",function() {
        if ($(this).val()) {
          $(this).closest("div.input-container").addClass("input-has-value");
        } else {
          $(this).closest("div.input-container").removeClass("input-has-value");
        }
      });
    };

    var initialize = function() {
      addFormFocusEventHandler();
      addFormValueEventHandler();
    };

    initialize();

label {
   color: transparent;
   display: block;
 }
 input[type=text] {
   display: block;
   border-width: 0 0 1px !important;
   border-radius: 0;
   border-style: solid;
   border-color: rgba(0,0.12);
 }
 .input-focused:not(.input-invalid) label {
   color: rgb(16,108,200);
 }
 .input-focused:not(.input-invalid) input[type=text] {
   border-color: rgb(16,200);
 }
 .input-has-value:not(.input-invalid):not(.input-focused) label {
   color: #595959;
 }
 .input-invalid.input-focused label,.input-invalid.input-has-value label {
   color: #ff0000;
 }
 .input-invalid input[type=text] {
   border-color: #ff0000;
 }
 .input-invalid input[type=text]::-webkit-input-placeholder {
   color: #ff0000;
 }
 .input-invalid input[type=text]::-webkit-input-placeholder::after {
   content: "\2716";
   /* "X" */
   font-size: 18px;
   color: #ff0000;
   padding-right: 0;
   float: right;
 }
 .input-valid input[type=text]::-webkit-input-placeholder::after {
   content: "\2714";
   /* checkmark */
   font-size: 18px;
   color: #438D5B;
   padding-right: 0;
   float: right;
 }
 .input-invalid input[type=text]::-webkit-input-placeholder::after {
   visibility: visible;
 }

<script src="https://code.jquery.com/jquery-1.12.0.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="stylesheet" />
<div class="container">
  <div class="row">
    <div class="col-xs-12 input-container input-required">
      <label for="merchantAddress">Merchant Address</label>
      <input type="text" class="full-width" id="merchantAddress" placeholder="Merchant Address" />
    </div>
    <div class="col-xs-12 input-container input-valid">
      <label for="merchantCity">Merchant City</label>
      <input type="text" class="full-width" id="merchantCity" placeholder="Merchant City" value="" />
    </div>
    <div class="col-xs-12 input-container input-invalid">
      <label for="merchantState">Merchant State Code</label>
      <input type="text" class="full-width" id="merchantState" placeholder="Merchant State Code" value="" />
    </div>
    <div class="col-xs-12 input-container input-invalid input-required">
      <label for="merchantZip">Merchant Zip Code</label>
      <input type="text" class="full-width" id="merchantZip" placeholder="Merchant Zip Code" value="Bad Data" />
    </div>
  </div>
</div>

Note: I would not recommend using the placeholder pseudo-element or its child pseudo-element for this purpose but then if you still wish to proceed the above answer would work for you.

为什么以上版本无法在Chrome v47及更高版本中使用？

正如Pete Talks Web在评论中指出的那样,上面的内容似乎不适用于Chrome v47,而它适用于Chrome v43.这似乎是因为在输入文本后如何隐藏占位符伪元素(:: – webkit-input-placeholder)的关键区别.在v43中,visibility属性用于隐藏它,而在v47中,它看起来像display：none.我无法访问v47,但假设这是基于在Opera中观察到的也使用WebKit的行为.还添加了！important.这个以及将属性添加为内联样式的事实意味着不可能仅使用CSS来覆盖它.因此,一旦输入文本,就无法使伪元素可见.

最新的Chrome会发生什么？

在Chrome v50.0.2638.0 dev-m中,提供的小提琴本身不起作用.也就是说,不会显示十字标记和刻度标记.似乎WebKit已经开始禁止向:: – webkit-input-placeholder添加伪元素.这是我一直期待发生的一件事,这正是我在答案中添加该注释的原因.

替代解决方案：

另一种解决方案是将伪元素添加到包装器div并将其定位为apt.在下面的片段中,我已将输入和伪元素更改为内联块,相对定位伪元素并向其添加负边距.这些使它出现在输入框的右边缘附近. (我还添加了宽度：标签的100％使其跨越整条线.)

var addFormFocusEventHandler = function() {
  var placeholder;
  // using the document Syntax in case input & container added to DOM dynamically
  $(document).on("focus",function() {
    $(this).closest("div.input-container").addClass("input-focused");
    placeholder = $(this).prop("placeholder");
    $(this).prop("placeholder"," ");
  }).on("blur",function() {
    $(this).closest("div.input-container").removeClass("input-focused");
    $(this).prop("placeholder",placeholder);
    placeholder = "";
  });
};
var addFormValueEventHandler = function() {
  // using the document Syntax in case input & container added to DOM dynamically
  $(document).on("blur",function() {
    if ($(this).val()) {
      $(this).closest("div.input-container").addClass("input-has-value");
    } else {
      $(this).closest("div.input-container").removeClass("input-has-value");
    }
  });
};

var initialize = function() {
  addFormFocusEventHandler();
  addFormValueEventHandler();
};

initialize();

label {
  color: transparent;
  display: block;
  width: 100%; /* add this */
}
input[type=text] {
  display: inline-block; /* modify this */
  border-width: 0 0 1px !important;
  border-radius: 0;
  border-style: solid;
  border-color: rgba(0,0.12);
}
.input-focused:not(.input-invalid) label {
  color: rgb(16,200);
}
.input-focused:not(.input-invalid) input[type=text] {
  border-color: rgb(16,200);
}
.input-has-value:not(.input-invalid):not(.input-focused) label {
  color: #595959;
}
.input-invalid.input-focused label,.input-invalid.input-has-value label {
  color: #ff0000;
}
.input-invalid input[type=text] {
  border-color: #ff0000;
}
.input-invalid input[type=text]::-webkit-input-placeholder {
  color: #ff0000;
}
.input-invalid::after { /* change the selector */
  position: relative; /* add this */
  display: inline-block; /* add this */
  margin-left: -1em; /* add this */
  content: "\2716";  /* "X" */
  font-size: 18px;
  color: #ff0000;
}
.input-valid::after {/* change the seletor */
  position: relative; /* add this */
  display: inline-block; /* add this */
  margin-left: -1em; /* add this */
  content: "\2714";  /* checkmark */
  font-size: 18px;
  color: #438D5B;
}

<script src="https://code.jquery.com/jquery-1.12.0.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="stylesheet" />
<div class="container">
  <div class="row">
    <div class="col-xs-12 input-container input-required">
      <label for="merchantAddress">Merchant Address</label>
      <input type="text" class="full-width" id="merchantAddress" placeholder="Merchant Address" />
    </div>
    <div class="col-xs-12 input-container input-valid">
      <label for="merchantCity">Merchant City</label>
      <input type="text" class="full-width" id="merchantCity" placeholder="Merchant City" value="" />
    </div>
    <div class="col-xs-12 input-container input-invalid">
      <label for="merchantState">Merchant State Code</label>
      <input type="text" class="full-width" id="merchantState" placeholder="Merchant State Code" value="" />
    </div>
    <div class="col-xs-12 input-container input-invalid input-required">
      <label for="merchantZip">Merchant Zip Code</label>
      <input type="text" class="full-width" id="merchantZip" placeholder="Merchant Zip Code" value="Bad Data" />
    </div>
  </div>
</div>

原文地址：https://www.jb51.cc/html/231517.html

html – CSS伪元素input-placeholder :: after在文本框中显示有无值

解决方法

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