1、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。键盘输入设备enter
let code = '';

let lastTime, nextTime;

let lastCode, nextCode;

window.document.onkeypress = (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(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;

}
let code = '';

let lastTime, nextTime;

let lastCode, nextCode;

window.document.onkeypress = (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(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;

}PS:下面看下js获取USB扫码枪数据的代码PS:下面看下js获取USB扫码枪数据的代码PS:下面看下js获取USB扫码枪数据的代码前言前言找了很多相关的教程不太好用,汲取各家之长总结精简了一下原理原理

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
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) {// IE

nextCode = e.keyCode

} else if (e.which) {// Netscape/Firefox/Opera

nextCode = 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 96-105

if((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Enter

if(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;

}

}
}
window.onload = (e)=> {

document.onkeydown = (e)=> {


let nextCode,nextTime = '';


let lastTime = this.lastTime;


let code = this.code;

if (window.event) {// IE

nextCode = e.keyCode

} else if (e.which) {// Netscape/Firefox/Opera

nextCode = 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 96-105

if((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Enter

if(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;

}

}
}总结总结总结