javascript ASCII和Hex互转

<script>

var symbols = " !\"#$%&'()*+,-./0123456789:;<=>?@";

var loAZ = "abcdefghijklmnopqrstuvwxyz";

symbols+= loAZ.toUpperCase();

symbols+= "[\\]^_`";

symbols+= loAZ;

symbols+= "{|}~";

//Hex to ASCII

function toAscii(str)

{

    valueStr = str.toLowerCase();

    var hex = "0123456789abcdef";

    var text = "";

    var i=0;

    for( i=0; i<valueStr.length; i=i+2 )

    {

        var char1 = valueStr.charAt(i);

        if ( char1 == ':' )

        {

            i++;

            char1 = valueStr.charAt(i);

        }

        var char2 = valueStr.charAt(i+1);

        var num1 = hex.indexOf(char1);

        var num2 = hex.indexOf(char2);

        var value = num1 << 4;

        value = value | num2;

        var valueInt = parseInt(value);

        var symbolIndex = valueInt - 32;

        var ch = '?';

        if ( symbolIndex >= 0 && value <= 126 )

        {

            ch = symbols.charAt(symbolIndex)

        }

        text += ch;

    }

    return text;

}

//ASCII to Hex

function toHex(str)

{

    var valueStr = str;

    var hexChars = "0123456789abcdef";

    var text = "";

    for( i=0; i<valueStr.length; i++ )

    {

        var oneChar = valueStr.charAt(i);

        var asciiValue = symbols.indexOf(oneChar) + 32;

        var index1 = asciiValue % 16;

        var index2 = (asciiValue - index1)/16;

        if ( text != "" ) text += ":";

        text += hexChars.charAt(index2);

        text += hexChars.charAt(index1);

    }

    return text;

}

</script>