复制代码 代码如下:
<script type="text/javascript"> <br><br>var base64encodechars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; <br>var base64decodechars = new Array( <br>-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, <br>-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, <br>-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, <br>52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, <br>-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, <br>15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, <br>-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, <br>41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1); <br><br>function base64encode(str) { <br>var out, i, len; <br>var c1, c2, c3; <br>len = str.length; <br>i = 0; <br>out = ""; <br>while (i < len) { <br>c1 = str.charCodeAt(i++) & 0xff; <br>if (i == len) { <br>out += base64encodechars.charAt(c1 >> 2); <br>out += base64encodechars.charAt((c1 & 0x3) << 4); <br>out += "=="; <br>break; <br>} <br>c2 = str.charCodeAt(i++); <br>if (i == len) { <br>out += base64encodechars.charAt(c1 >> 2); <br>out += base64encodechars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xf0) >> 4)); <br>out += base64encodechars.charAt((c2 & 0xf) << 2); <br>out += "="; <br>break; <br>} <br>c3 = str.charCodeAt(i++); <br>out += base64encodechars.charAt(c1 >> 2); <br>out += base64encodechars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xf0) >> 4)); <br>out += base64encodechars.charAt(((c2 & 0xf) << 2) | ((c3 & 0xc0) >> 6)); <br>out += base64encodechars.charAt(c3 & 0x3f); <br>} <br>return out; <br>} <br><br>function base64decode(str) { <br>var c1, c2, c3, c4; <br>var i, len, out; <br><br>len = str.length; <br><br>i = 0; <br>out = ""; <br>while (i < len) { <br><br>do { <br>c1 = base64decodechars[str.charCodeAt(i++) & 0xff]; <br>} while (i < len && c1 == -1); <br>if (c1 == -1) <br>break; <br><br>do { <br>c2 = base64decodechars[str.charCodeAt(i++) & 0xff]; <br>} while (i < len && c2 == -1); <br>if (c2 == -1) <br>break; <br><br>out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4)); <br><br>do { <br>c3 = str.charCodeAt(i++) & 0xff; <br>if (c3 == 61) <br>return out; <br>c3 = base64decodechars[c3]; <br>} while (i < len && c3 == -1); <br>if (c3 == -1) <br>break; <br><br>out += String.fromCharCode(((c2 & 0xf) << 4) | ((c3 & 0x3c) >> 2)); <br><br>do { <br>c4 = str.charCodeAt(i++) & 0xff; <br>if (c4 == 61) <br>return out; <br>c4 = base64decodechars[c4]; <br>} while (i < len && c4 == -1); <br>if (c4 == -1) <br>break; <br>out += String.fromCharCode(((c3 & 0x03) << 6) | c4); <br>} <br>return out; <br>} <br></script>
