Js Base64 加解密
作者:Dreamer
出处:http://www.dreamerlzy.com/blog/article/detail/js-base64
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//base64 加密 function base64_encode(str) { var c1, c2, c3; var base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; var i = 0, len = str.length, string = ''; while (i < len) { c1 = str.charCodeAt(i++) & 0xff; if (i == len) { string += base64EncodeChars.charAt(c1 >> 2); string += base64EncodeChars.charAt((c1 & 0x3) << 4); string += "=="; break; } c2 = str.charCodeAt(i++); if (i == len) { string += base64EncodeChars.charAt(c1 >> 2); string += base64EncodeChars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4)); string += base64EncodeChars.charAt((c2 & 0xF) << 2); string += "="; break; } c3 = str.charCodeAt(i++); string += base64EncodeChars.charAt(c1 >> 2); string += base64EncodeChars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4)); string += base64EncodeChars.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >> 6)); string += base64EncodeChars.charAt(c3 & 0x3F) } return string } //base64 解密 function base64_decode(str) { var c1, c2, c3, c4; 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 ); var i = 0, len = str.length, string = ''; while (i < len) { do { c1 = base64DecodeChars[str.charCodeAt(i++) & 0xff] } while ( i < len && c1 == -1 ); if (c1 == -1) break; do { c2 = base64DecodeChars[str.charCodeAt(i++) & 0xff] } while ( i < len && c2 == -1 ); if (c2 == -1) break; string += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4)); do { c3 = str.charCodeAt(i++) & 0xff; if (c3 == 61) return string; c3 = base64DecodeChars[c3] } while ( i < len && c3 == -1 ); if (c3 == -1) break; string += String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2)); do { c4 = str.charCodeAt(i++) & 0xff; if (c4 == 61) return string; c4 = base64DecodeChars[c4] } while ( i < len && c4 == -1 ); if (c4 == -1) break; string += String.fromCharCode(((c3 & 0x03) << 6) | c4) } return string; }