模拟退格按钮JS

Nik*_*nko 6 javascript jquery

我想创建一个自定义退格按钮,其逻辑与键盘上的"退格"按钮相同.我使用以下代码:

function backSpace()
{
    var e = jQuery.Event("keyup");
    e.which = 8; // # Some key code value
    e.keyCode = 8;
    $("mainDiv").trigger(e);
}
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<!DOCTYPE html>
<html>
    <head>
        <link rel="stylesheet" href="styles.css" type="text/css" media="screen" />
        <script src="formulas.js"></script>
        <script src="http://code.jquery.com/jquery-1.11.3.js"></script>
        <meta name="viewport" content="width=device-width initial-scale=1.0 maximum-scale=1.0 user-scalable=no"/>
    </head>

    <button onclick="backSpace()">backSpace</button>
    <body id="main" spellcheck="false">
        <div id = "mainDiv" contenteditable="true"></div>
    </body>
</html>
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但它不起作用.我不明白我做错了什么.我花了很多时间来解决这个问题,但我还没有解决它.请帮帮我.

小智 6

这段代码对我来说效果很好。您可以逐个清除插入符号位置的字母或清除选择

var textbox = document.getElementById('textbox');

function backspace()
{
var ss = textbox.selectionStart;
var se = textbox.selectionEnd;
var ln  = textbox.value.length;

var textbefore = textbox.value.substring( 0, ss );    //text in front of selected text
var textselected = textbox.value.substring( ss, se ); //selected text
var textafter = textbox.value.substring( se, ln );    //text following selected text

if(ss==se) // if no text is selected
{
textbox.value = textbox.value.substring(0, ss-1 ) + textbox.value.substring(se, ln );
textbox.focus();
textbox.selectionStart = ss-1;
textbox.selectionEnd = ss-1;
}
else // if some text is selected
{
textbox.value = textbefore + textafter ;
textbox.focus();
textbox.selectionStart = ss;
textbox.selectionEnd = ss;
}

}
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<textarea id="textbox"></textarea>
<div class="button" onclick="backspace()" > BACKSPACE_BUTTON </div>
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希望有帮助!


shy*_*.me 3

对@CosLu 的回答的补充

JSBin 这里也有

function backSpace() {
  p = document.getElementById("mainDiv");
  c = getCaretPosition(p);
  console.log(getCaretPosition(p));
  str = $("#mainDiv").html();
  if (c > 0 && c <= str.length) {
    $("#mainDiv").focus().html(str.substring(0, c - 1) + str.substring(c, str.length));

    p.focus();
    var textNode = p.firstChild;
    var caret = c - 1; 
    var range = document.createRange();
    range.setStart(textNode, caret);
    range.setEnd(textNode, caret);
    var sel = window.getSelection();
    sel.removeAllRanges();
    sel.addRange(range);
  }
}

$.fn.setCursorPosition = function(pos) {
  this.each(function(index, elem) {
    if (elem.setSelectionRange) {
      elem.setSelectionRange(pos, pos);
    } else if (elem.createTextRange) {
      var range = elem.createTextRange();
      range.collapse(true);
      range.moveEnd('character', pos);
      range.moveStart('character', pos);
      range.select();
    }
  });
  return this;
};

function getCaretPosition(editableDiv) {
  var caretPos = 0,
    sel, range;
  if (window.getSelection) {
    sel = window.getSelection();
    if (sel.rangeCount) {
      range = sel.getRangeAt(0);
      if (range.commonAncestorContainer.parentNode == editableDiv) {
        caretPos = range.endOffset;
      }
    }
  } else if (document.selection && document.selection.createRange) {
    range = document.selection.createRange();
    if (range.parentElement() == editableDiv) {
      var tempEl = document.createElement("span");
      editableDiv.insertBefore(tempEl, editableDiv.firstChild);
      var tempRange = range.duplicate();
      tempRange.moveToElementText(tempEl);
      tempRange.setEndPoint("EndToEnd", range);
      caretPos = tempRange.text.length;
    }
  }
  return caretPos;
}
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<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>JS Bin</title>
  <script src="http://code.jquery.com/jquery-1.11.3.js"></script>
</head>

<body>
  <button onclick="backSpace()">backSpace</button>
  <div id="mainDiv" contenteditable="true">aahahtext</div>
</body>

</html>
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