js获取扫码枪输入数据的方法

方法"/>

js获取扫码枪输入数据的方法

扫码枪相当于键盘输入设备，输入一连串数字后加一个enter键。

但在实际开发中需要区分是扫描枪输入还是键盘用户输入，区别在于扫码枪输入很快。

let code = '';let lastTime, nextTime;let lastCode, nextCode;window.document.onkeypress = (e) => {if (window.event) { // IEnextCode = e.keyCode;} else if (e.which) { // Netscape/Firefox/OperanextCode = 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(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;}

下面看下js获取USB扫码枪数据的代码：

原理：

扫码枪扫描到的条形码每一位会触发一次onkeydown事件

比如扫描条码位‘1234567890’的条形码，会连续执行10次onkeydown事件

条码扫描到最后一位，会直接触发Enter

需要引入jQuery，我这里用的是vue

window.onload = (e)=> {document.onkeydown = (e)=> {let nextCode,nextTime = '';let lastTime = this.lastTime;let code = this.code;if (window.event) {// IEnextCode = e.keyCode} else if (e.which) {// Netscape/Firefox/OperanextCode = e.which}nextTime = new Date().getTime();//字母上方 数字键0-9 对应键码值 48-57; 数字键盘 数字键0-9 对应键码值 96-105if((nextCode>=48&&nextCode<=57) || (nextCode>=96&&nextCode<=105)){let codes = {'48':48,'49':49,'50':50,'51':51,'52':52,'53':53,'54':54,'55':55,'56':56,'57':57,'96':48,'97':49,'98':50,'99':51,'100':52,'101':53,'102':54,'103':55,'104':56,'105':57};nextCode = codes[nextCode];nextTime = new Date().getTime();}// 第二次输入延迟两秒，删除之前的数据重新计算if(nextTime && lastTime && nextTime-lastTime>2000){code = String.fromCharCode(nextCode);}else{code += String.fromCharCode(nextCode)}// 保存数据this.nextCode = nextCode;this.lastTime = nextTime;this.code = code;// 键入Enterif(e.which == 13) {// 判断 code 长度（这里就获取到条码值了，以下业务自由发挥）code = $.trim(code)if (code.length == 13) {this.$message('A类条码:' + code);} else if (code.length == 23) {this.$message('B类条码:' + code);} else if (code.length == 0) {this.$message('请输入条码');} else{this.$message('条码不合法：' + code);}//键入回车务必清空code值this.code = ''return false;}}
}