当由javascript产生的元素激活时，javascript不起作用

debugcn 发表于 Dev

亨利5400

我遇到了一个看似简单但令人费解的javascript问题。这里有两个片段：两者几乎相同，除了后一个代码段的黄色输入框由Javascript生成。

这两个代码之间的区别是：

<table><tbody><tr class="newdiv"><td style="background:yellow">enter</td></tr></tbody></table> click the yellow box!
<br><textarea id="result"></textarea>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script>
// the script below enables typing 'enter' into textarea by clicking the yellow box.
$('.newdiv>td').click(function(){
    var range = document.createRange();
    range.selectNodeContents(this);  
    var sel = window.getSelection(); 
    sel.removeAllRanges(); 
    sel.addRange(range);
    insertAtCaret('result', sel);return false;
});
function insertAtCaret(areaId, text) {
  var txtarea = document.getElementById(areaId);
  if (!txtarea) {
    return;
  }
  var scrollPos = txtarea.scrollTop;
  var strPos = 0;
  var br = ((txtarea.selectionStart || txtarea.selectionStart == '0') ?
    "ff" : (document.selection ? "ie" : false));
  if (br == "ie") {
    txtarea.focus();
    var range = document.selection.createRange();
    range.moveStart('character', -txtarea.value.length);
    strPos = range.text.length;
  } else if (br == "ff") {
    strPos = txtarea.selectionStart;
  }
  var front = (txtarea.value).substring(0, strPos);
  var back = (txtarea.value).substring(strPos, txtarea.value.length);
  txtarea.value = front + text + back;
  strPos = strPos + text.length;
  txtarea.scrollTop = scrollPos;
}
</script>

<button onclick="myfunction()">show</button>
<div id="show"></div>
<br><textarea class="txta" id="result"></textarea>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script>
function myfunction(){
document.getElementById('show').innerHTML = `
<table><tbody><tr class="newdiv"><td style="background:yellow">enter</td></tr></tbody></table> click the yellow box!
`;
}
// the script below enables typing 'enter' into textarea by clicking the yellow box.
$('.newdiv>td').click(function(){
    var range = document.createRange();
    range.selectNodeContents(this);  
    var sel = window.getSelection(); 
    sel.removeAllRanges(); 
    sel.addRange(range);
    insertAtCaret('result', sel);return false;
});
function insertAtCaret(areaId, text) {
  var txtarea = document.getElementById(areaId);
  if (!txtarea) {
    return;
  }
  var scrollPos = txtarea.scrollTop;
  var strPos = 0;
  var br = ((txtarea.selectionStart || txtarea.selectionStart == '0') ?
    "ff" : (document.selection ? "ie" : false));
  if (br == "ie") {
    txtarea.focus();
    var range = document.selection.createRange();
    range.moveStart('character', -txtarea.value.length);
    strPos = range.text.length;
  } else if (br == "ff") {
    strPos = txtarea.selectionStart;
  }
  var front = (txtarea.value).substring(0, strPos);
  var back = (txtarea.value).substring(strPos, txtarea.value.length);
  txtarea.value = front + text + back;
  strPos = strPos + text.length;
  txtarea.scrollTop = scrollPos;
}
</script>

第二个片段的黄色框由以下部分产生：

function myfunction(){
document.getElementById('show').innerHTML = `
<table><tbody><tr class="newdiv"><td style="background:yellow">enter</td></tr></tbody></table> click the yellow box!
`;
}

第二个片段通过javascript函数生成黄色框，并且键入enter由jquery起作用。我的问题是：为什么函数在第一个代码段中起作用，而在第二个代码段中却不起作用，尽管它们之间的差异（以我的拙见）似乎并不影响功能本身？

超级明星

请使用以下代码更改代码。

从

$('.newdiv>td').click(function(){
    var range = document.createRange();
    range.selectNodeContents(this);  
    var sel = window.getSelection(); 
    sel.removeAllRanges(); 
    sel.addRange(range);
    insertAtCaret('result', sel);return false;
});

至

$(document).on('click', '.newdiv>td', function(){
    var range = document.createRange();
    range.selectNodeContents(this);  
    var sel = window.getSelection(); 
    sel.removeAllRanges(); 
    sel.addRange(range);
    insertAtCaret('result', sel);return false;
});

参考答案

<button onclick="myfunction()">show</button>
<div id="show"></div>
<br><textarea class="txta" id="result"></textarea>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script>
function myfunction(){
document.getElementById('show').innerHTML = `
<table><tbody><tr class="newdiv"><td style="background:yellow">enter</td></tr></tbody></table> click the yellow box!
`;
}
// the script below enables typing 'enter' into textarea by clicking the yellow box.
$(document).on('click', '.newdiv>td', function(){
    var range = document.createRange();
    range.selectNodeContents(this);  
    var sel = window.getSelection(); 
    sel.removeAllRanges(); 
    sel.addRange(range);
    insertAtCaret('result', sel);return false;
});
function insertAtCaret(areaId, text) {
  var txtarea = document.getElementById(areaId);
  if (!txtarea) {
    return;
  }
  var scrollPos = txtarea.scrollTop;
  var strPos = 0;
  var br = ((txtarea.selectionStart || txtarea.selectionStart == '0') ?
    "ff" : (document.selection ? "ie" : false));
  if (br == "ie") {
    txtarea.focus();
    var range = document.selection.createRange();
    range.moveStart('character', -txtarea.value.length);
    strPos = range.text.length;
  } else if (br == "ff") {
    strPos = txtarea.selectionStart;
  }
  var front = (txtarea.value).substring(0, strPos);
  var back = (txtarea.value).substring(strPos, txtarea.value.length);
  txtarea.value = front + text + back;
  strPos = strPos + text.length;
  txtarea.scrollTop = scrollPos;
}
</script>

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