javascript实现的字符串与十六进制表示字符串相互转换方法

javascript实现的字符串与十六进制表示字符串相互转换方法_javascript技巧

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发布： 2016-05-16 15:49:43

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本文实例讲述了javascript实现的字符串与十六进制表示字符串相互转换方法。分享给大家供大家参考。具体如下：

之所以写这个，是因为发现SQL注入和XSS中经常利用十六进制表示的字符串，比如
SELECT CONCAT(0x68656c6c6f);
得到的是hello

<!DOCTYPE html>
<html>
 <head>
  <title>Hex-Char Bi-Converter</title>
 </head>
 <body>
  <div class="mainContainer">
   <label for="from" id="fromLabel">String</label>
   <input type="text" name="from" id="from" />
   <input type="button" name="exchange" id="exchange" value="<=>" />
   <label for="to" id="toLabel">Hex</label>
   <input type="text" name="to" id="to" />
   <input type="button" name="convert" id="convert" value="Convert" />
  </div>
  <script type="text/javascript" src="js/jquery-1.9.1.min.js"></script>
  <script type="text/javascript">
   var curMode = 0; // curMode: 0 represents String to Hex, 1 from Hex to String
   var fromToLabelArray = ["Hex", "String"];
   $(function() {
    $("#convert").click(function() {
     var fromVal = $("#from").val();
     var toVal = 
      curMode === 0 
      &#63; 
      strToHexCharCode(fromVal) 
      :
      hexCharCodeToStr(fromVal);
     $("#to").val(toVal);
    });
    $("#exchange").click(function() {
     $("#fromLabel").text(fromToLabelArray[curMode]);
     $("#toLabel").text(fromToLabelArray[1-curMode]);
     curMode = 1 - curMode;
    });
   });
   function strToHexCharCode(str) {
    if(str === "")
     return "";
    var hexCharCode = [];
    hexCharCode.push("0x");    
    for(var i = 0; i < str.length; i++) {
     hexCharCode.push((str.charCodeAt(i)).toString(16));
    }
    return hexCharCode.join("");
   }
   function hexCharCodeToStr(hexCharCodeStr) {
    var trimedStr = hexCharCodeStr.trim();
    var rawStr = 
      trimedStr.substr(0,2).toLowerCase() === "0x"
      &#63; 
      trimedStr.substr(2) 
      : 
      trimedStr;
    var len = rawStr.length;
    if(len % 2 !== 0) {
     alert("Illegal Format ASCII Code!");
        return "";
    }
    var curCharCode;
    var resultStr = [];
    for(var i = 0; i < len;i = i + 2) {
     curCharCode = parseInt(rawStr.substr(i, 2), 16); // ASCII Code Value
     resultStr.push(String.fromCharCode(curCharCode));
    }
    return resultStr.join("");
   }
  </script>
 </body>
</html>

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希望本文所述对大家的javascript程序设计有所帮助。