用js得到图片的base64编码rt[解决办法]http://blog.dengsa.com/?p45[解决办法]base64 加密解密HTML code
用js得到图片的base64编码
rt
[解决办法]
http://blog.dengsa.com/?p=45
[解决办法]
base64 加密解密
- HTML code
<!doctype html public "-//w3c//dtd html 4.01 transitional//en" "http://www.w3.org/tr/html4/loose.dtd"><html><head><meta http-equiv="content-type" content="text/html; charset=gb2312"><title>base64编码加密</title><script language="javascript"> 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) { 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; out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4)); 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)); 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)) }</script></head><body style="padding-left:50px;"><h1 align="center">base64编码加密</h1><form name="f">原码<br><textarea name="source" rows=4 cols=60 wrap="soft"></textarea><br><br>base64 encode<br><textarea name="output" rows=4 cols=60 wrap="soft"></textarea><br><br>base64 decode<br><textarea name="decode" rows=4 cols=60 wrap="soft"></textarea><br><br><input type=button value="转换" onclick="doit()"></form></body></html>
[解决办法]
支持HTML5的浏览器现在可以直接得到
function getBase64Image(img) {
var canvas = document.createElement("canvas");
canvas.width = img.width;
canvas.height = img.height;
var ctx = canvas.getContext("2d");
ctx.drawImage(img, 0, 0);
var dataURL = canvas.toDataURL("image/png");
return dataURL.replace(/^data:image\/(png|jpg);base64,/, "");
}