常用JS转码算法

一：Base64

<script>
    var base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; 
    var base64DecodeChars = new Array(-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 
        52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, 
        -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 
        15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, 
        -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 
        41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1); 
    function base64encode(str) { //传递的str必须是 字符串类型 
        var out, i, len,c1, c2, c3; 
        len = str.length; 
        i = 0; 
        out = ""; 
        while(i < len) { 
            c1 = str.charCodeAt(i++) & 0xff;
            if(i == len) 
            { 
                out += base64EncodeChars.charAt(c1 >> 2); 
                out += base64EncodeChars.charAt((c1 & 0x3) << 4); 
                out += "=="; 
                break; 
            } 
            c2 = str.charCodeAt(i++); 
            if(i == len) 
            { 
                out += base64EncodeChars.charAt(c1 >> 2); 
                out += base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4)); 
                out += base64EncodeChars.charAt((c2 & 0xF) << 2); 
                out += "="; 
                break; 
            } 
            c3 = str.charCodeAt(i++); 
            out += base64EncodeChars.charAt(c1 >> 2); 
            out += base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4)); 
            out += base64EncodeChars.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >>6)); 
            out += base64EncodeChars.charAt(c3 & 0x3F); 
        } 
        return out; 
    } 
   alert('http://localhost:8080/html/line_detail.html?id='+base64encode('1')+'&lsiId='+base64encode('5'));

   function base64decode(str) { 
        var c1, c2, c3, c4,i, len, out;  
        len = str.length; 
        i = 0; 
        out = ""; 
        while(i < len) { 
        //c1
        do { 
            c1 = base64DecodeChars[str.charCodeAt(i++) & 0xff]; 
        } while(i < len && c1 == -1); 
        if(c1 == -1) 
            break; 
        //c2
        do { 
            c2 = base64DecodeChars[str.charCodeAt(i++) & 0xff]; 
        } while(i < len && c2 == -1); 
        if(c2 == -1) 
            break; 
        out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4)); 
        //c3
        do { 
            c3 = str.charCodeAt(i++) & 0xff; 
            if(c3 == 61) 
            return out; 
            c3 = base64DecodeChars[c3]; 
        } while(i < len && c3 == -1); 
        if(c3 == -1) 
            break; 
        out += String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2)); 
        //c4
        do { 
            c4 = str.charCodeAt(i++) & 0xff; 
            if(c4 == 61) 
            return out; 
            c4 = base64DecodeChars[c4]; 
        } while(i < len && c4 == -1); 
        if(c4 == -1) 
            break; 
        out += String.fromCharCode(((c3 & 0x03) << 6) | c4); 
        } 
        return out; 
    } 
   alert('http://localhost:8080/html/line_detail.html?id='+base64decode(base64encode('1'))+'&lsiId='+base64decode(base64encode('5')));
 </script>