CodePen

HTML

            
              <html>
<head>
<script type="text/javascript">
    function copy_data(val){
     var a = document.getElementById(val.id).value
     document.getElementById("copy_to").value = a
  .replace(/a/g, '001')
  .replace(/b/g, '002')
  .replace(/v/g, '008');
    }
</script>
</head>
<body>
From:&nbsp;&nbsp;&nbsp; <input type="text" name ="a" id="copy_from" onkeyup="copy_data(this)"/><br>
To:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <input type="text" name ="b" id="copy_to"/><br>
</body>
</html>
            
          
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CSS

            
              
            
          
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via CSS Lint

JS

            
              
            
          
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