JS实现扫码枪扫描二维码功能

 this.start = new Date().getTime() let code = '' let lastTime, nextTime let lastCode, nextCode let that = this window.document.onkeypress = function (e) { if (window.event) { // IE nextCode = e.keyCode } else if (e.which) { // Netscape/Firefox/Opera nextCode = e.which } console.time() console.log('nextCode', nextCode) if (e.which === 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) console.log('扫码结束') console.timeEnd() that.parseQRCode(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) { console.log('扫码开始。。。') code += e.key } if (lastCode && lastTime && nextTime - lastTime > 500) { // 当扫码前有keypress事件时,防止首字缺失 console.log('防止首字缺失。。。') code = e.key } else if (lastCode && lastTime) { console.log('扫码中。。。') code += e.key } lastCode = nextCode lastTime = nextTime }