JS常用加密编码与算法实例总结

本文实例讲述了JS常用加密编码与算法。分享给大家供大家参考，具体如下：

一：UTF8编码函数

function URLEncode(Str){ if(Str==null||Str=="")  return ""; var newStr=""; function toCase(sStr){  return sStr.toString(16).toUpperCase();  } for(var i=0,icode,len=Str.length;i<len;i++){  icode=Str.charCodeAt(i);  if( icode<0x10)   newStr+="%0"+icode.toString(16).toUpperCase();  else if(icode<0x80){   if(icode==0x20)    newStr+="+";   else if((icode>=0x30&&icode<=0x39)||(icode>=0x41&&icode<=0x5A)||(icode>=0x61&&icode<=0x7A))    newStr+=Str.charAt(i);   else    newStr+="%"+toCase(icode);   }  else if(icode<0x800){   newStr+="%"+toCase(0xC0+(icode>>6));   newStr+="%"+toCase(0x80+icode%0x40);   }  else{   newStr+="%"+toCase(0xE0+(icode>>12));   newStr+="%"+toCase(0x80+(icode>>6)%0x40);   newStr+="%"+toCase(0x80+icode%0x40);   }  } return newStr; }

二：Base64编码,解码函数

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) {  var out, i, len;  var 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;}function base64decode(str) {  var c1, c2, c3, c4;  var 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;}function utf16to8(str) {  var out, i, len, c;  out = "";  len = str.length;  for(i = 0; i < len; i++) {  c = str.charCodeAt(i);  if ((c >= 0x0001) && (c <= 0x007F)) {    out += str.charAt(i);  } else if (c > 0x07FF) {    out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F));    out += String.fromCharCode(0x80 | ((c >> 6) & 0x3F));    out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));  } else {    out += String.fromCharCode(0xC0 | ((c >> 6) & 0x1F));    out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));  }  }  return out;}function utf8to16(str) {  var out, i, len, c;  var char2, char3;  out = "";  len = str.length;  i = 0;  while(i < len) {  c = str.charCodeAt(i++);  switch(c >> 4)  {   case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:    // 0xxxxxxx    out += str.charAt(i-1);    break;   case 12: case 13:    // 110x xxxx 10xx xxxx    char2 = str.charCodeAt(i++);    out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));    break;   case 14:    // 1110 xxxx 10xx xxxx 10xx xxxx    char2 = str.charCodeAt(i++);    char3 = str.charCodeAt(i++);    out += String.fromCharCode(((c & 0x0F) << 12) |            ((char2 & 0x3F) << 6) |            ((char3 & 0x3F) << 0));    break;  }  }  return out;}function doit() {  var f = document.f  f.output.value = base64encode(utf16to8(f.source.value))  f.decode.value = utf8to16(base64decode(f.output.value))}