JS生成URL二维码

需求：项目中需要在UI界面有一个二维码，扫码后可以跳转到二维码包含的URL。

解决方案：在前端用js生成一个包含URL等信息的二维码。

实现：

方案一、

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> 
<html> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 
<title>js_canvas_download</title> 
<script type='text/javascript' src='http://cdn.staticfile.org/jquery/2.1.1/jquery.min.js'></script> 
<script type="text/javascript" src="http://cdn.staticfile.org/jquery.qrcode/1.0/jquery.qrcode.min.js"></script> 
</head> 
<body> 
<div id="qrcode"></div> 
<a id="download" download="qrcode.jpg"></a> 
<button id="save">save</button> 
</body> 
</html> 
<script>
    jQuery('#qrcode').qrcode({  75, height: 75, text: window.location.href });
    $("#save").click(function () {
        var canvas = $('#qrcode').find("canvas").get(0);
        var url = canvas.toDataURL('image/jpeg');
        $("#download").attr('href', url).get(0).click();
        return false;
    });
</script>

方案二、

2.1 js类库qrcode.js

var QRCode;

(function () {
//---------------------------------------------------------------------
// QRCode for JavaScript
//
// Copyright (c) 2009
//
//---------------------------------------------------------------------
function QR8bitByte(data) {
this.mode = QRMode.MODE_8BIT_BYTE;
this.data = data;
this.parsedData = [];

// Added to support UTF-8 Characters
for (var i = 0, l = this.data.length; i < l; i++) {
var byteArray = [];
var code = this.data.charCodeAt(i);

if (code > 0x10000) {
byteArray[0] = 0xF0 | ((code & 0x1C0000) >>> 18);
byteArray[1] = 0x80 | ((code & 0x3F000) >>> 12);
byteArray[2] = 0x80 | ((code & 0xFC0) >>> 6);
byteArray[3] = 0x80 | (code & 0x3F);
} else if (code > 0x800) {
byteArray[0] = 0xE0 | ((code & 0xF000) >>> 12);
byteArray[1] = 0x80 | ((code & 0xFC0) >>> 6);
byteArray[2] = 0x80 | (code & 0x3F);
} else if (code > 0x80) {
byteArray[0] = 0xC0 | ((code & 0x7C0) >>> 6);
byteArray[1] = 0x80 | (code & 0x3F);
} else {
byteArray[0] = code;
}

this.parsedData.push(byteArray);
}

this.parsedData = Array.prototype.concat.apply([], this.parsedData);

if (this.parsedData.length != this.data.length) {
this.parsedData.unshift(191);
this.parsedData.unshift(187);
this.parsedData.unshift(239);
}
}

QR8bitByte.prototype = {
getLength: function (buffer) {
return this.parsedData.length;
},
write: function (buffer) {
for (var i = 0, l = this.parsedData.length; i < l; i++) {
buffer.put(this.parsedData[i], 8);
}
}
};

function QRCodeModel(typeNumber, errorCorrectLevel) {
this.typeNumber = typeNumber;
this.errorCorrectLevel = errorCorrectLevel;
this.modules = null;
this.moduleCount = 0;
this.dataCache = null;
this.dataList = [];
}

function QRPolynomial(num, shift) {
if (num.length == undefined) throw new Error(num.length + "/" + shift);
var offset = 0;
while (offset < num.length && num[offset] == 0) offset++;
this.num = new Array(num.length - offset + shift);
for (var i = 0; i < num.length - offset; i++) this.num[i] = num[i + offset];
}

function QRRSBlock(totalCount, dataCount) {
this.totalCount = totalCount, this.dataCount = dataCount;
}

function QRBitBuffer() {
this.buffer = [], this.length = 0;
}

QRCodeModel.prototype = {
"addData": function (data) {
var newData = new QR8bitByte(data);
this.dataList.push(newData), this.dataCache = null;
},
"isDark": function (row, col) {
if (row < 0 || this.moduleCount <= row || col < 0 || this.moduleCount <= col) throw new Error(row + "," + col);
return this.modules[row][col];
},
"getModuleCount": function () {
return this.moduleCount;
},
"make": function () {
this.makeImpl(!1, this.getBestMaskPattern());
},
"makeImpl": function (test, maskPattern) {
this.moduleCount = this.typeNumber * 4 + 17, this.modules = new Array(this.moduleCount);
for (var row = 0; row < this.moduleCount; row++) {
this.modules[row] = new Array(this.moduleCount);
for (var col = 0; col < this.moduleCount; col++) this.modules[row][col] = null;
}
this.setupPositionProbePattern(0, 0),
this.setupPositionProbePattern(this.moduleCount - 7, 0),
this.setupPositionProbePattern(0, this.moduleCount - 7),
this.setupPositionAdjustPattern(), this.setupTimingPattern(),
this.setupTypeInfo(test, maskPattern),
this.typeNumber >= 7 && this.setupTypeNumber(test),
this.dataCache == null && (this.dataCache = QRCodeModel.createData(this.typeNumber, this.errorCorrectLevel, this.dataList)), this.mapData(this.dataCache, maskPattern);
},
"setupPositionProbePattern": function (row, col) {
for (var r = -1; r <= 7; r++) {
if (row + r <= -1 || this.moduleCount <= row + r) continue;
for (var c = -1; c <= 7; c++) {
if (col + c <= -1 || this.moduleCount <= col + c) continue;
0 <= r && r <= 6 && (c == 0 || c == 6) || 0 <= c && c <= 6 && (r == 0 || r == 6) || 2 <= r && r <= 4 && 2 <= c && c <= 4 ? this.modules[row + r][col + c] = !0 : this.modules[row + r][col + c] = !1;
}
}
},
"getBestMaskPattern": function () {
var minLostPoint = 0, pattern = 0;
for (var i = 0; i < 8; i++) {
this.makeImpl(!0, i);
var lostPoint = QRUtil.getLostPoint(this);
if (i == 0 || minLostPoint > lostPoint) minLostPoint = lostPoint, pattern = i;
}
return pattern;
},
"createMovieClip": function (target_mc, instance_name, depth) {
var qr_mc = target_mc.createEmptyMovieClip(instance_name, depth), cs = 1;
this.make();
for (var row = 0; row < this.modules.length; row++) {
var y = row * cs;
for (var col = 0; col < this.modules[row].length; col++) {
var x = col * cs, dark = this.modules[row][col];
dark && (qr_mc.beginFill(0, 100), qr_mc.moveTo(x, y), qr_mc.lineTo(x + cs, y), qr_mc.lineTo(x + cs, y + cs), qr_mc.lineTo(x, y + cs), qr_mc.endFill());
}
}
return qr_mc;
},
"setupTimingPattern": function () {
for (var r = 8; r < this.moduleCount - 8; r++) {
if (this.modules[r][6] != null) continue;
this.modules[r][6] = r % 2 == 0;
}
for (var c = 8; c < this.moduleCount - 8; c++) {
if (this.modules[6][c] != null) continue;
this.modules[6][c] = c % 2 == 0;
}
},
"setupPositionAdjustPattern": function () {
var pos = QRUtil.getPatternPosition(this.typeNumber);
for (var i = 0; i < pos.length; i++) for (var j = 0; j < pos.length; j++) {
var row = pos[i], col = pos[j];
if (this.modules[row][col] != null) continue;
for (var r = -2; r <= 2; r++) for (var c = -2; c <= 2; c++) r == -2 || r == 2 || c == -2 || c == 2 || r == 0 && c == 0 ? this.modules[row + r][col + c] = !0 : this.modules[row + r][col + c] = !1;
}
},
"setupTypeNumber": function (test) {
var bits = QRUtil.getBCHTypeNumber(this.typeNumber);
for (var i = 0; i < 18; i++) {
var mod = !test && (bits >> i & 1) == 1;
this.modules[Math.floor(i / 3)][i % 3 + this.moduleCount - 8 - 3] = mod;
}
for (var i = 0; i < 18; i++) {
var mod = !test && (bits >> i & 1) == 1;
this.modules[i % 3 + this.moduleCount - 8 - 3][Math.floor(i / 3)] = mod;
}
},
"setupTypeInfo": function (test, maskPattern) {
var data = this.errorCorrectLevel << 3 | maskPattern, bits = QRUtil.getBCHTypeInfo(data);
for (var i = 0; i < 15; i++) {
var mod = !test && (bits >> i & 1) == 1;
i < 6 ? this.modules[i][8] = mod : i < 8 ? this.modules[i + 1][8] = mod : this.modules[this.moduleCount - 15 + i][8] = mod;
}
for (var i = 0; i < 15; i++) {
var mod = !test && (bits >> i & 1) == 1;
i < 8 ? this.modules[8][this.moduleCount - i - 1] = mod : i < 9 ? this.modules[8][15 - i - 1 + 1] = mod : this.modules[8][15 - i - 1] = mod;
}
this.modules[this.moduleCount - 8][8] = !test;
},
"mapData": function (data, maskPattern) {
var inc = -1, row = this.moduleCount - 1, bitIndex = 7, byteIndex = 0;
for (var col = this.moduleCount - 1; col > 0; col -= 2) {
col == 6 && col--;
for (; ;) {
for (var c = 0; c < 2; c++) if (this.modules[row][col - c] == null) {
var dark = !1;
byteIndex < data.length && (dark = (data[byteIndex] >>> bitIndex & 1) == 1);
var mask = QRUtil.getMask(maskPattern, row, col - c);
mask && (dark = !dark), this.modules[row][col - c] = dark, bitIndex-- , bitIndex == -1 && (byteIndex++ , bitIndex = 7);
}
row += inc;
if (row < 0 || this.moduleCount <= row) {
row -= inc, inc = -inc;
break;
}
}
}
}
}, QRCodeModel.PAD0 = 236, QRCodeModel.PAD1 = 17, QRCodeModel.createData = function (typeNumber, errorCorrectLevel, dataList) {
var rsBlocks = QRRSBlock.getRSBlocks(typeNumber, errorCorrectLevel), buffer = new QRBitBuffer;
for (var i = 0; i < dataList.length; i++) {
var data = dataList[i];
buffer.put(data.mode, 4), buffer.put(data.getLength(), QRUtil.getLengthInBits(data.mode, typeNumber)), data.write(buffer);
}
var totalDataCount = 0;
for (var i = 0; i < rsBlocks.length; i++) totalDataCount += rsBlocks[i].dataCount;
if (buffer.getLengthInBits() > totalDataCount * 8) throw new Error("code length overflow. (" + buffer.getLengthInBits() + ">" + totalDataCount * 8 + ")");
buffer.getLengthInBits() + 4 <= totalDataCount * 8 && buffer.put(0, 4);
while (buffer.getLengthInBits() % 8 != 0) buffer.putBit(!1);
for (; ;) {
if (buffer.getLengthInBits() >= totalDataCount * 8) break;
buffer.put(QRCodeModel.PAD0, 8);
if (buffer.getLengthInBits() >= totalDataCount * 8) break;
buffer.put(QRCodeModel.PAD1, 8);
}
return QRCodeModel.createBytes(buffer, rsBlocks);
}, QRCodeModel.createBytes = function (buffer, rsBlocks) {
var offset = 0, maxDcCount = 0, maxEcCount = 0, dcdata = new Array(rsBlocks.length), ecdata = new Array(rsBlocks.length);
for (var r = 0; r < rsBlocks.length; r++) {
var dcCount = rsBlocks[r].dataCount, ecCount = rsBlocks[r].totalCount - dcCount;
maxDcCount = Math.max(maxDcCount, dcCount), maxEcCount = Math.max(maxEcCount, ecCount), dcdata[r] = new Array(dcCount);
for (var i = 0; i < dcdata[r].length; i++) dcdata[r][i] = 255 & buffer.buffer[i + offset];
offset += dcCount;
var rsPoly = QRUtil.getErrorCorrectPolynomial(ecCount), rawPoly = new QRPolynomial(dcdata[r], rsPoly.getLength() - 1), modPoly = rawPoly.mod(rsPoly);
ecdata[r] = new Array(rsPoly.getLength() - 1);
for (var i = 0; i < ecdata[r].length; i++) {
var modIndex = i + modPoly.getLength() - ecdata[r].length;
ecdata[r][i] = modIndex >= 0 ? modPoly.get(modIndex) : 0;
}
}
var totalCodeCount = 0;
for (var i = 0; i < rsBlocks.length; i++) totalCodeCount += rsBlocks[i].totalCount;
var data = new Array(totalCodeCount), index = 0;
for (var i = 0; i < maxDcCount; i++) for (var r = 0; r < rsBlocks.length; r++) i < dcdata[r].length && (data[index++] = dcdata[r][i]);
for (var i = 0; i < maxEcCount; i++) for (var r = 0; r < rsBlocks.length; r++) i < ecdata[r].length && (data[index++] = ecdata[r][i]);
return data;
};

for (var i = 0; i < 8; i++) QRMath.EXP_TABLE[i] = 1 << i;

for (var i = 8; i < 256; i++) QRMath.EXP_TABLE[i] = QRMath.EXP_TABLE[i - 4] ^ QRMath.EXP_TABLE[i - 5] ^ QRMath.EXP_TABLE[i - 6] ^ QRMath.EXP_TABLE[i - 8];

for (var i = 0; i < 255; i++) QRMath.LOG_TABLE[QRMath.EXP_TABLE[i]] = i;

QRPolynomial.prototype = {
"get": function (index) {
return this.num[index];
},
"getLength": function () {
return this.num.length;
},
"multiply": function (e) {
var num = new Array(this.getLength() + e.getLength() - 1);
for (var i = 0; i < this.getLength(); i++) for (var j = 0; j < e.getLength(); j++) num[i + j] ^= QRMath.gexp(QRMath.glog(this.get(i)) + QRMath.glog(e.get(j)));
return new QRPolynomial(num, 0);
},
"mod": function (e) {
if (this.getLength() - e.getLength() < 0) return this;
var ratio = QRMath.glog(this.get(0)) - QRMath.glog(e.get(0)), num = new Array(this.getLength());
for (var i = 0; i < this.getLength(); i++) num[i] = this.get(i);
for (var i = 0; i < e.getLength(); i++) num[i] ^= QRMath.gexp(QRMath.glog(e.get(i)) + ratio);
return (new QRPolynomial(num, 0)).mod(e);
}
}, QRRSBlock.RS_BLOCK_TABLE = [[1, 26, 19], [1, 26, 16], [1, 26, 13], [1, 26, 9], [1, 44, 34], [1, 44, 28], [1, 44, 22], [1, 44, 16], [1, 70, 55], [1, 70, 44], [2, 35, 17], [2, 35, 13], [1, 100, 80], [2, 50, 32], [2, 50, 24], [4, 25, 9], [1, 134, 108], [2, 67, 43], [2, 33, 15, 2, 34, 16], [2, 33, 11, 2, 34, 12], [2, 86, 68], [4, 43, 27], [4, 43, 19], [4, 43, 15], [2, 98, 78], [4, 49, 31], [2, 32, 14, 4, 33, 15], [4, 39, 13, 1, 40, 14], [2, 121, 97], [2, 60, 38, 2, 61, 39], [4, 40, 18, 2, 41, 19], [4, 40, 14, 2, 41, 15], [2, 146, 116], [3, 58, 36, 2, 59, 37], [4, 36, 16, 4, 37, 17], [4, 36, 12, 4, 37, 13], [2, 86, 68, 2, 87, 69], [4, 69, 43, 1, 70, 44], [6, 43, 19, 2, 44, 20], [6, 43, 15, 2, 44, 16], [4, 101, 81], [1, 80, 50, 4, 81, 51], [4, 50, 22, 4, 51, 23], [3, 36, 12, 8, 37, 13], [2, 116, 92, 2, 117, 93], [6, 58, 36, 2, 59, 37], [4, 46, 20, 6, 47, 21], [7, 42, 14, 4, 43, 15], [4, 133, 107], [8, 59, 37, 1, 60, 38], [8, 44, 20, 4, 45, 21], [12, 33, 11, 4, 34, 12], [3, 145, 115, 1, 146, 116], [4, 64, 40, 5, 65, 41], [11, 36, 16, 5, 37, 17], [11, 36, 12, 5, 37, 13], [5, 109, 87, 1, 110, 88], [5, 65, 41, 5, 66, 42], [5, 54, 24, 7, 55, 25], [11, 36, 12], [5, 122, 98, 1, 123, 99], [7, 73, 45, 3, 74, 46], [15, 43, 19, 2, 44, 20], [3, 45, 15, 13, 46, 16], [1, 135, 107, 5, 136, 108], [10, 74, 46, 1, 75, 47], [1, 50, 22, 15, 51, 23], [2, 42, 14, 17, 43, 15], [5, 150, 120, 1, 151, 121], [9, 69, 43, 4, 70, 44], [17, 50, 22, 1, 51, 23], [2, 42, 14, 19, 43, 15], [3, 141, 113, 4, 142, 114], [3, 70, 44, 11, 71, 45], [17, 47, 21, 4, 48, 22], [9, 39, 13, 16, 40, 14], [3, 135, 107, 5, 136, 108], [3, 67, 41, 13, 68, 42], [15, 54, 24, 5, 55, 25], [15, 43, 15, 10, 44, 16], [4, 144, 116, 4, 145, 117], [17, 68, 42], [17, 50, 22, 6, 51, 23], [19, 46, 16, 6, 47, 17], [2, 139, 111, 7, 140, 112], [17, 74, 46], [7, 54, 24, 16, 55, 25], [34, 37, 13], [4, 151, 121, 5, 152, 122], [4, 75, 47, 14, 76, 48], [11, 54, 24, 14, 55, 25], [16, 45, 15, 14, 46, 16], [6, 147, 117, 4, 148, 118], [6, 73, 45, 14, 74, 46], [11, 54, 24, 16, 55, 25], [30, 46, 16, 2, 47, 17], [8, 132, 106, 4, 133, 107], [8, 75, 47, 13, 76, 48], [7, 54, 24, 22, 55, 25], [22, 45, 15, 13, 46, 16], [10, 142, 114, 2, 143, 115], [19, 74, 46, 4, 75, 47], [28, 50, 22, 6, 51, 23], [33, 46, 16, 4, 47, 17], [8, 152, 122, 4, 153, 123], [22, 73, 45, 3, 74, 46], [8, 53, 23, 26, 54, 24], [12, 45, 15, 28, 46, 16], [3, 147, 117, 10, 148, 118], [3, 73, 45, 23, 74, 46], [4, 54, 24, 31, 55, 25], [11, 45, 15, 31, 46, 16], [7, 146, 116, 7, 147, 117], [21, 73, 45, 7, 74, 46], [1, 53, 23, 37, 54, 24], [19, 45, 15, 26, 46, 16], [5, 145, 115, 10, 146, 116], [19, 75, 47, 10, 76, 48], [15, 54, 24, 25, 55, 25], [23, 45, 15, 25, 46, 16], [13, 145, 115, 3, 146, 116], [2, 74, 46, 29, 75, 47], [42, 54, 24, 1, 55, 25], [23, 45, 15, 28, 46, 16], [17, 145, 115], [10, 74, 46, 23, 75, 47], [10, 54, 24, 35, 55, 25], [19, 45, 15, 35, 46, 16], [17, 145, 115, 1, 146, 116], [14, 74, 46, 21, 75, 47], [29, 54, 24, 19, 55, 25], [11, 45, 15, 46, 46, 16], [13, 145, 115, 6, 146, 116], [14, 74, 46, 23, 75, 47], [44, 54, 24, 7, 55, 25], [59, 46, 16, 1, 47, 17], [12, 151, 121, 7, 152, 122], [12, 75, 47, 26, 76, 48], [39, 54, 24, 14, 55, 25], [22, 45, 15, 41, 46, 16], [6, 151, 121, 14, 152, 122], [6, 75, 47, 34, 76, 48], [46, 54, 24, 10, 55, 25], [2, 45, 15, 64, 46, 16], [17, 152, 122, 4, 153, 123], [29, 74, 46, 14, 75, 47], [49, 54, 24, 10, 55, 25], [24, 45, 15, 46, 46, 16], [4, 152, 122, 18, 153, 123], [13, 74, 46, 32, 75, 47], [48, 54, 24, 14, 55, 25], [42, 45, 15, 32, 46, 16], [20, 147, 117, 4, 148, 118], [40, 75, 47, 7, 76, 48], [43, 54, 24, 22, 55, 25], [10, 45, 15, 67, 46, 16], [19, 148, 118, 6, 149, 119], [18, 75, 47, 31, 76, 48], [34, 54, 24, 34, 55, 25], [20, 45, 15, 61, 46, 16]], QRRSBlock.getRSBlocks = function (typeNumber, errorCorrectLevel) {
var rsBlock = QRRSBlock.getRsBlockTable(typeNumber, errorCorrectLevel);
if (rsBlock == undefined) throw new Error("bad rs block @ typeNumber:" + typeNumber + "/errorCorrectLevel:" + errorCorrectLevel);
var length = rsBlock.length / 3, list = [];
for (var i = 0; i < length; i++) {
var count = rsBlock[i * 3 + 0], totalCount = rsBlock[i * 3 + 1], dataCount = rsBlock[i * 3 + 2];
for (var j = 0; j < count; j++) list.push(new QRRSBlock(totalCount, dataCount));
}
return list;
}, QRRSBlock.getRsBlockTable = function (typeNumber, errorCorrectLevel) {
switch (errorCorrectLevel) {
case QRErrorCorrectLevel.L:
return QRRSBlock.RS_BLOCK_TABLE[(typeNumber - 1) * 4 + 0];
case QRErrorCorrectLevel.M:
return QRRSBlock.RS_BLOCK_TABLE[(typeNumber - 1) * 4 + 1];
case QRErrorCorrectLevel.Q:
return QRRSBlock.RS_BLOCK_TABLE[(typeNumber - 1) * 4 + 2];
case QRErrorCorrectLevel.H:
return QRRSBlock.RS_BLOCK_TABLE[(typeNumber - 1) * 4 + 3];
default:
return undefined;
}
}, QRBitBuffer.prototype = {
"get": function (index) {
var bufIndex = Math.floor(index / 8);
return (this.buffer[bufIndex] >>> 7 - index % 8 & 1) == 1;
},
"put": function (num, length) {
for (var i = 0; i < length; i++) this.putBit((num >>> length - i - 1 & 1) == 1);
},
"getLengthInBits": function () {
return this.length;
},
"putBit": function (bit) {
var bufIndex = Math.floor(this.length / 8);
this.buffer.length <= bufIndex && this.buffer.push(0), bit && (this.buffer[bufIndex] |= 128 >>> this.length % 8), this.length++;
}
};
var QRCodeLimitLength = [[17, 14, 11, 7], [32, 26, 20, 14], [53, 42, 32, 24], [78, 62, 46, 34], [106, 84, 60, 44], [134, 106, 74, 58], [154, 122, 86, 64], [192, 152, 108, 84], [230, 180, 130, 98], [271, 213, 151, 119], [321, 251, 177, 137], [367, 287, 203, 155], [425, 331, 241, 177], [458, 362, 258, 194], [520, 412, 292, 220], [586, 450, 322, 250], [644, 504, 364, 280], [718, 560, 394, 310], [792, 624, 442, 338], [858, 666, 482, 382], [929, 711, 509, 403], [1003, 779, 565, 439], [1091, 857, 611, 461], [1171, 911, 661, 511], [1273, 997, 715, 535], [1367, 1059, 751, 593], [1465, 1125, 805, 625], [1528, 1190, 868, 658], [1628, 1264, 908, 698], [1732, 1370, 982, 742], [1840, 1452, 1030, 790], [1952, 1538, 1112, 842], [2068, 1628, 1168, 898], [2188, 1722, 1228, 958], [2303, 1809, 1283, 983], [2431, 1911, 1351, 1051], [2563, 1989, 1423, 1093], [2699, 2099, 1499, 1139], [2809, 2213, 1579, 1219], [2953, 2331, 1663, 1273]];

function _isSupportCanvas() {
return typeof CanvasRenderingContext2D != "undefined";
}

// android 2.x doesn't support Data-URI spec
function _getAndroid() {
var android = false;
var sAgent = navigator.userAgent;

if (/android/i.test(sAgent)) { // android
android = true;
aMat = sAgent.toString().match(/android ([0-9].[0-9])/i);

if (aMat && aMat[1]) {
android = parseFloat(aMat[1]);
}
}

return android;
}

var svgDrawer = (function () {

var Drawing = function (el, htOption) {
this._el = el;
this._htOption = htOption;
};

Drawing.prototype.draw = function (oQRCode) {
var _htOption = this._htOption;
var _el = this._el;
var nCount = oQRCode.getModuleCount();
var nWidth = Math.floor(_htOption.width / nCount);
var nHeight = Math.floor(_htOption.height / nCount);

this.clear();

function makeSVG(tag, attrs) {
var el = document.createElementNS('http://www.w3.org/2000/svg', tag);
for (var k in attrs)
if (attrs.hasOwnProperty(k)) el.setAttribute(k, attrs[k]);
return el;
}

var svg = makeSVG("svg", { 'viewBox': '0 0 ' + String(nCount) + " " + String(nCount), 'width': '100%', 'height': '100%', 'fill': _htOption.colorLight });
svg.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns:xlink", "http://www.w3.org/1999/xlink");
_el.appendChild(svg);

svg.appendChild(makeSVG("rect", { "fill": _htOption.colorDark, "width": "1", "height": "1", "id": "template" }));

for (var row = 0; row < nCount; row++) {
for (var col = 0; col < nCount; col++) {
if (oQRCode.isDark(row, col)) {
var child = makeSVG("use", { "x": String(row), "y": String(col) });
child.setAttributeNS("http://www.w3.org/1999/xlink", "href", "#template")
svg.appendChild(child);
}
}
}
};
Drawing.prototype.clear = function () {
while (this._el.hasChildNodes())
this._el.removeChild(this._el.lastChild);
};
return Drawing;
})();

var useSVG = document.documentElement.tagName.toLowerCase() === "svg";

// Drawing in DOM by using Table tag
var Drawing = useSVG ? svgDrawer : !_isSupportCanvas() ? (function () {
var Drawing = function (el, htOption) {
this._el = el;
this._htOption = htOption;
};

/**
* Draw the QRCode
*
* @param {QRCode} oQRCode
*/
Drawing.prototype.draw = function (oQRCode) {
var _htOption = this._htOption;
var _el = this._el;
var nCount = oQRCode.getModuleCount();
var nWidth = Math.floor(_htOption.width / nCount);
var nHeight = Math.floor(_htOption.height / nCount);
var aHTML = ['<table style="border:0;border-collapse:collapse;">'];

for (var row = 0; row < nCount; row++) {
aHTML.push('<tr>');

for (var col = 0; col < nCount; col++) {
aHTML.push('<td style="border:0;border-collapse:collapse;padding:0;margin:0;' + nWidth + 'px;height:' + nHeight + 'px;background-color:' + (oQRCode.isDark(row, col) ? _htOption.colorDark : _htOption.colorLight) + ';"></td>');
}

aHTML.push('</tr>');
}

aHTML.push('</table>');
_el.innerHTML = aHTML.join('');

// Fix the margin values as real size.
var elTable = _el.childNodes[0];
var nLeftMarginTable = (_htOption.width - elTable.offsetWidth) / 2;
var nTopMarginTable = (_htOption.height - elTable.offsetHeight) / 2;
if (nLeftMarginTable > 0 && nTopMarginTable > 0) {
elTable.style.margin = nTopMarginTable + "px " + nLeftMarginTable + "px";
}
};

/**
* Clear the QRCode
*/
Drawing.prototype.clear = function () {
this._el.innerHTML = '';
};

return Drawing;
})() : (function () { // Drawing in Canvas
function _onMakeImage() {
this._elImage.src = this._elCanvas.toDataURL("image/png");
this._elImage.style.display = "block";
this._elCanvas.style.display = "none";
}

// Android 2.1 bug workaround
// http://code.google.com/p/android/issues/detail?id=5141
if (this._android && this._android <= 2.1) {
var factor = 1 / window.devicePixelRatio;
var drawImage = CanvasRenderingContext2D.prototype.drawImage;
CanvasRenderingContext2D.prototype.drawImage = function (image, sx, sy, sw, sh, dx, dy, dw, dh) {
if (("nodeName" in image) && /img/i.test(image.nodeName)) {
for (var i = arguments.length - 1; i >= 1; i--) {
arguments[i] = arguments[i] * factor;
}
} else if (typeof dw == "undefined") {
arguments[1] *= factor;
arguments[2] *= factor;
arguments[3] *= factor;
arguments[4] *= factor;
}

drawImage.apply(this, arguments);
};
}

/**
* Check whether the user's browser supports Data URI or not
*
* @private
* @param {Function} fSuccess Occurs if it supports Data URI
* @param {Function} fFail Occurs if it doesn't support Data URI
*/
function _safeSetDataURI(fSuccess, fFail) {
var self = this;
self._fFail = fFail;
self._fSuccess = fSuccess;

// Check it just once
if (self._bSupportDataURI === null) {
var el = document.createElement("img");
var fOnError = function () {
self._bSupportDataURI = false;

if (self._fFail) {
_fFail.call(self);
}
};
var fOnSuccess = function () {
self._bSupportDataURI = true;

if (self._fSuccess) {
self._fSuccess.call(self);
}
};

el.onabort = fOnError;
el.onerror = fOnError;
el.onload = fOnSuccess;
el.src = "data:image/gif;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg=="; // the Image contains 1px data.
return;
} else if (self._bSupportDataURI === true && self._fSuccess) {
self._fSuccess.call(self);
} else if (self._bSupportDataURI === false && self._fFail) {
self._fFail.call(self);
}
};

/**
* Drawing QRCode by using canvas
*
* @constructor
* @param {HTMLElement} el
* @param {Object} htOption QRCode Options
*/
var Drawing = function (el, htOption) {
this._bIsPainted = false;
this._android = _getAndroid();

this._htOption = htOption;
this._elCanvas = document.createElement("canvas");
this._elCanvas.width = htOption.width;
this._elCanvas.height = htOption.height;
el.appendChild(this._elCanvas);
this._el = el;
this._oContext = this._elCanvas.getContext("2d");
this._bIsPainted = false;
this._elImage = document.createElement("img");
this._elImage.alt = "Scan me!";
this._elImage.style.display = "none";
this._el.appendChild(this._elImage);
this._bSupportDataURI = null;
};

/**
* Draw the QRCode
*
* @param {QRCode} oQRCode
*/
Drawing.prototype.draw = function (oQRCode) {
var _elImage = this._elImage;
var _oContext = this._oContext;
var _htOption = this._htOption;

var nCount = oQRCode.getModuleCount();
var nWidth = _htOption.width / nCount;
var nHeight = _htOption.height / nCount;
var nRoundedWidth = Math.round(nWidth);
var nRoundedHeight = Math.round(nHeight);

_elImage.style.display = "none";
this.clear();

for (var row = 0; row < nCount; row++) {
for (var col = 0; col < nCount; col++) {
var bIsDark = oQRCode.isDark(row, col);
var nLeft = col * nWidth;
var nTop = row * nHeight;
_oContext.strokeStyle = bIsDark ? _htOption.colorDark : _htOption.colorLight;
_oContext.lineWidth = 1;
_oContext.fillStyle = bIsDark ? _htOption.colorDark : _htOption.colorLight;
_oContext.fillRect(nLeft, nTop, nWidth, nHeight);

// 안티 앨리어싱 방지 처리
_oContext.strokeRect(
Math.floor(nLeft) + 0.5,
Math.floor(nTop) + 0.5,
nRoundedWidth,
nRoundedHeight
);

_oContext.strokeRect(
Math.ceil(nLeft) - 0.5,
Math.ceil(nTop) - 0.5,
nRoundedWidth,
nRoundedHeight
);
}
}

this._bIsPainted = true;
};

/**
* Make the image from Canvas if the browser supports Data URI.
*/
Drawing.prototype.makeImage = function () {
if (this._bIsPainted) {
_safeSetDataURI.call(this, _onMakeImage);
}
};

/**
* Return whether the QRCode is painted or not
*
* @return {Boolean}
*/
Drawing.prototype.isPainted = function () {
return this._bIsPainted;
};

/**
* Clear the QRCode
*/
Drawing.prototype.clear = function () {
this._oContext.clearRect(0, 0, this._elCanvas.width, this._elCanvas.height);
this._bIsPainted = false;
};

/**
* @private
* @param {Number} nNumber
*/
Drawing.prototype.round = function (nNumber) {
if (!nNumber) {
return nNumber;
}

return Math.floor(nNumber * 1000) / 1000;
};

return Drawing;
})();

/**
* Get the type by string length
*
* @private
* @param {String} sText
* @param {Number} nCorrectLevel
* @return {Number} type
*/
function _getTypeNumber(sText, nCorrectLevel) {
var nType = 1;
var length = _getUTF8Length(sText);

for (var i = 0, len = QRCodeLimitLength.length; i <= len; i++) {
var nLimit = 0;

switch (nCorrectLevel) {
case QRErrorCorrectLevel.L:
nLimit = QRCodeLimitLength[i][0];
break;
case QRErrorCorrectLevel.M:
nLimit = QRCodeLimitLength[i][1];
break;
case QRErrorCorrectLevel.Q:
nLimit = QRCodeLimitLength[i][2];
break;
case QRErrorCorrectLevel.H:
nLimit = QRCodeLimitLength[i][3];
break;
}

if (length <= nLimit) {
break;
} else {
nType++;
}
}

if (nType > QRCodeLimitLength.length) {
throw new Error("Too long data");
}

return nType;
}

function _getUTF8Length(sText) {
var replacedText = encodeURI(sText).toString().replace(/\%[0-9a-fA-F]{2}/g, 'a');
return replacedText.length + (replacedText.length != sText ? 3 : 0);
}

/**
* @class QRCode
* @constructor
* @example
* new QRCode(document.getElementById("test"), "http://jindo.dev.naver.com/collie");
*
* @example
* var oQRCode = new QRCode("test", {
* text : "http://naver.com",
* width : 128,
* height : 128
* });
*
* oQRCode.clear(); // Clear the QRCode.
* oQRCode.makeCode("http://map.naver.com"); // Re-create the QRCode.
*
* @param {HTMLElement|String} el target element or 'id' attribute of element.
* @param {Object|String} vOption
* @param {String} vOption.text QRCode link data
* @param {Number} [vOption.width=256]
* @param {Number} [vOption.height=256]
* @param {String} [vOption.colorDark="#000000"]
* @param {String} [vOption.colorLight="#ffffff"]
* @param {QRCode.CorrectLevel} [vOption.correctLevel=QRCode.CorrectLevel.H] [L|M|Q|H]
*/
QRCode = function (el, vOption) {
this._htOption = {
256,
height: 256,
typeNumber: 4,
colorDark: "#000000",
colorLight: "#ffffff",
correctLevel: QRErrorCorrectLevel.H
};

if (typeof vOption === 'string') {
vOption = {
text: vOption
};
}

// Overwrites options
if (vOption) {
for (var i in vOption) {
this._htOption[i] = vOption[i];
}
}

if (typeof el == "string") {
el = document.getElementById(el);
}

this._android = _getAndroid();
this._el = el;
this._oQRCode = null;
this._oDrawing = new Drawing(this._el, this._htOption);

if (this._htOption.text) {
this.makeCode(this._htOption.text);
}
};

/**
* Make the QRCode
*
* @param {String} sText link data
*/
QRCode.prototype.makeCode = function (sText) {
this._oQRCode = new QRCodeModel(_getTypeNumber(sText, this._htOption.correctLevel), this._htOption.correctLevel);
this._oQRCode.addData(sText);
this._oQRCode.make();
this._el.title = sText;
this._oDrawing.draw(this._oQRCode);
this.makeImage();
};

/**
* Make the Image from Canvas element
* - It occurs automatically
* - Android below 3 doesn't support Data-URI spec.
*
* @private
*/
QRCode.prototype.makeImage = function () {
if (typeof this._oDrawing.makeImage == "function" && (!this._android || this._android >= 3)) {
this._oDrawing.makeImage();
}
};

/**
* Clear the QRCode
*/
QRCode.prototype.clear = function () {
this._oDrawing.clear();
};

/**
* @name QRCode.CorrectLevel
*/
QRCode.CorrectLevel = QRErrorCorrectLevel;
})();

2.2 html页面

<!DOCTYPE html>
<html>
<head>
    <title></title>
    <meta charset="utf-8"/>
    <script src="js/qrcode.js"></script>
    <style>
        #qrcode{
            /*text-align: center;*/
            /*display: table-cell;*/
            /* 96px;*/
            /*height: 96px;*/
            /*vertical-align:middle;*/
            /*position: relative;*/
        }
    </style>
</head>
<body>
<div id="qrcode">
</div>

<input type="text" id="getval"/> <button id="send">点击更换验证码</button>
<script>
    window.onload =function(){
        var qrcode = new QRCode(document.getElementById("qrcode"), {
            width : 96,//设置宽高
            height : 96
        });
        qrcode.makeCode("http://www.baidu.com");
        document.getElementById("send").onclick =function(){
            qrcode.makeCode(document.getElementById("getval").value);
        }
    }
</script>
</body>
</html>

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原文地址：https://www.cnblogs.com/johsan/p/10519146.html