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JS generates QR code

Mar 17, 2018 am 09:46 AM

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This time I will bring you JS to generate QR code. What are the precautions for JS to generate QR code? The following is a practical case, let’s take a look.

HTML code:

&lt;img style=&quot;display: none&quot; id=&quot;qrcode&quot; data-width=&quot;100&quot; data-height=&quot;100&quot; data-url=&quot;https://www.baidu.com/&quot;&gt;

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Related JS code:

/**
  * 生成二维码
  * data-width={宽度}
  * data-height={高度}
  * data-url={链接}
  * @param $ele
  */
 var generatorQRCODE = function ($ele) {
  $ele.hide();
  var params = $ele.data();
  if(!params['width'] || !params['height'] || !params['url']){
   console.log('生成二维码参数错误');
   return false;
  }
  var image = new Image();
  var imageUrl = "http://pan.baidu.com/share/qrcode?w=" + params['width'] + "&amp;h=" + params['height'] + "&amp;url=" + params['url'] + "";
  image.src = imageUrl;
  $ele.attr('src', imageUrl);
  $ele.show();
 };
 
 generatorQRCODE($("#qrcode"));

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Let me share with you other generated 2 QR code case:

Use jquery.qrcode to generate QR code

1. First, add the jquery library file and qrcode plug-in to the page

&lt;script type=&quot;text/javascript&quot; src=&quot;jquery.js&quot;&gt;&lt;/script&gt; 
&lt;script type=&quot;text/javascript&quot; src=&quot;jquery.qrcode.min.js&quot;&gt;&lt;/script&gt;

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2. Add the following code to the page where the QR code needs to be displayed:

&lt;p id=&quot;code&quot;&gt;&lt;/p&gt;

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3. Call the qrcode plug-in. Supports two methods of canvas and table for image rendering

canvas method:

$('#code').qrcode("http://www.baidu.com"); //任意字符串

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table method:

$("#code").qrcode({ 
  render: "table", //table方式 
  width: 200, //宽度 
  height:200, //高度 
  text: "www.helloweba.com" //任意内容 
});

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4. If the generated QR code content contains text, you need to Convert the string to UTF-8

Define the conversion method:

function toUtf8(str) {  
  var out, i, len, c;  
  out = "";  
  len = str.length;  
  for(i = 0; i &lt; len; i++) {  
    c = str.charCodeAt(i);  
    if ((c &gt;= 0x0001) &amp;&amp; (c &lt;= 0x007F)) {  
      out += str.charAt(i);  
    } else if (c &gt; 0x07FF) {  
      out += String.fromCharCode(0xE0 | ((c &gt;&gt; 12) &amp; 0x0F));  
      out += String.fromCharCode(0x80 | ((c &gt;&gt; 6) &amp; 0x3F));  
      out += String.fromCharCode(0x80 | ((c &gt;&gt; 0) &amp; 0x3F));  
    } else {  
      out += String.fromCharCode(0xC0 | ((c &gt;&gt; 6) &amp; 0x1F));  
      out += String.fromCharCode(0x80 | ((c &gt;&gt; 0) &amp; 0x3F));  
    }  
  }  
  return out;  
}

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Call the conversion method when generating:

var str = toUtf8("字符串测试！"); 
$('#code').qrcode(str);

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2. Dynamically generate in the Vue-cli project 2 QR code

1. Introduce qrcode--------npm install qrcode

2. Introduce

import QRCode from 'qrcode'  //定义生成二维码组件

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3 in main.js. Use it when needed Introduce

import QRCode from 'qrcode'   //引入生成二维码组件

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into the component that generates the QR code. 4. Define the generated location in HTML and pay attention to adding the style

&lt;template&gt;
 &lt;p id=&quot;query&quot;&gt;
  &lt;h1&gt;二维码：&lt;/h1&gt;
  &lt;canvas id=&quot;canvas&quot;&gt;&lt;/canvas&gt;
 &lt;/p&gt;
&lt;/template&gt;

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#canvas{
  width: 80%!important;
  height: auto!important;
 }

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5. Define the method to generate the QR code in js and call

//动态生成二维码
  useqrcode(){    //生成的二维码内容，可以添加变量　　　　this.QueryDetail='http://www.kspxzx.com/#/guard'+"?unique_code="+this.QueryDetail;var canvas = document.getElementById('canvas')
    QRCode.toCanvas(canvas, this.QueryDetail, function (error) {
    if (error) console.error(error)
    console.log('success!');
    })
  }

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I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!