JS - 获取扫码枪扫描到二维码数据的方法

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<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body id="main">
    
    <script>
        window.onload = function(e){
            
     
		  let code = ;
		  let lastTime, nextTime;
		  let lastCode, nextCode;
		  window.document.onkeypress = function(e){
            
     
		   if (window.event) {
            
      // IE
			nextCode = e.keyCode;
		   } else if (e.which) {
            
      // Netscape/Firefox/Opera
			nextCode = e.which;
		   }
		   if (nextCode === 13) {
            
     
			if (code.length < 3) return; // 手动输入的时间不会让code的长度大于2,所以这里只会对扫码枪有
		 
			console.log("获取到扫码枪输入的内容",code); // 获取到扫码枪输入的内容,做别的操作
		 
			code = ;
			lastCode = ;
			lastTime = ;
			return;
		   }
		   nextTime = new Date().getTime();
		   if (!lastTime && !lastCode) {
            
     
			code += e.key;
		   }
		 
		   if (lastCode && lastTime && nextTime - lastTime > 30) {
            
      // 当扫码前有keypress事件时,防止首字缺失
			code = e.key;
		   } else if (lastCode && lastTime) {
            
     
			code += e.key;
		   }
		   lastCode = nextCode;
		   lastTime = nextTime;
		  }
		}
    </script>
</body>

</html>
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