How to implement JavaScript to record the position of the cursor in the editor

How to implement JavaScript to record the position of the cursor in the editor_javascript skills

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Release： 2016-05-16 15:04:36

Original

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The example in this article describes the implementation method of JavaScript recording the position of the cursor in the editor. Share it with everyone for your reference, the details are as follows:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
</head>
<body>
<script type="text/javascript">
function $(ele){return document.getElementById(ele)}
//记录编辑器中的位置
   var selection_start;
   var selection_end;
   function savePos(textBox){
   var start=0;
   var end=0;
   if(typeof(textBox.selectionStart) == "number"){ // not ie
    //alert(typeof(textBox.selectionStart) );
    start = textBox.selectionStart;
    end = textBox.selectionEnd;
   }
   else if(document.selection){
    var range = document.selection.createRange();
    if(range.parentElement().id == textBox.id){
     var range_all = document.body.createTextRange();
     range_all.moveToElementText(textBox);
     for (start=0; range_all.compareEndPoints("StartToStart", range) < 0; start++)
      range_all.moveStart('character', 1);
     for (var i = 0; i <= start; i ++){
      if (textBox.value.charAt(i) == '/n')
       start++;
     }
      var range_all = document.body.createTextRange();
      range_all.moveToElementText(textBox);
      for (end = 0; range_all.compareEndPoints('StartToEnd', range) < 0; end ++)
       range_all.moveStart('character', 1);
       for (var i = 0; i <= end; i ++){
        if (textBox.value.charAt(i) == '/n')
         end ++;
       }
     }
    }
    selection_start = start;
    selection_end = end;
   }
</script>
<form action="" id="test">
<textarea id="t" onfocus="savePos(this);$('log').value=selection_start" onkeydown="savePos(this);$('log').value=selection_start" onmousedown="savePos(this);$('log').value=selection_start" onmouseup="savePos(this);$('log').value=selection_start" >
</textarea>
<input type="text" id="log" />
</form>
</body>
</html>

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