有什么方法使js獲取掃碼槍輸入數(shù)據(jù)

有什么方法使js獲取掃碼槍輸入數(shù)據(jù)？很多新手對(duì)此不是很清楚，為了幫助大家解決這個(gè)難題，下面小編將為大家詳細(xì)講解，有這方面需求的人可以來學(xué)習(xí)下，希望你能有所收獲。

1、掃碼槍相當(dāng)于鍵盤輸入設(shè)備，輸入一連串?dāng)?shù)字后加一個(gè)enter鍵。但在實(shí)際開發(fā)中需要區(qū)分是掃描槍輸入還是鍵盤用戶輸入，區(qū)別在于掃碼槍輸入很快。

 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; // 手動(dòng)輸入的時(shí)間不會(huì)讓code的長(zhǎng)度大于2，所以這里只會(huì)對(duì)掃碼槍有

     console.log(code); // 獲取到掃碼槍輸入的內(nèi)容，做別的操作

     code = '';
     lastCode = '';
     lastTime = '';
     return;
    }
    nextTime = new Date().getTime();
    if (!lastTime && !lastCode) {
     code += e.key;
    }

    if (lastCode && lastTime && nextTime - lastTime > 30) { // 當(dāng)掃碼前有keypress事件時(shí),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獲取USB掃碼槍數(shù)據(jù)的代碼

前言

找了很多相關(guān)的教程不太好用，汲取各家之長(zhǎng)總結(jié)精簡(jiǎn)了一下

原理

1. 掃碼槍掃描到的條形碼每一位會(huì)觸發(fā)一次onkeydown事件
2. 比如掃描條碼位‘1234567890'的條形碼，會(huì)連續(xù)執(zhí)行10次onkeydown事件
3. 條碼掃描到最后一位，會(huì)直接觸發(fā)Enter

需要引入jQuery，我這里用的是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 數(shù)字鍵0-9 對(duì)應(yīng)鍵碼值 48-57; 數(shù)字鍵盤 數(shù)字鍵0-9 對(duì)應(yīng)鍵碼值 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();
    }
    // 第二次輸入延遲兩秒，刪除之前的數(shù)據(jù)重新計(jì)算
    if(nextTime && lastTime && nextTime-lastTime>2000){
			code = String.fromCharCode(nextCode);
    }else{
    	code += String.fromCharCode(nextCode)
    }
    // 保存數(shù)據(jù)
    this.nextCode = nextCode;
    this.lastTime = nextTime;
    this.code = code;
  	// 鍵入Enter
    if(e.which == 13) {
      // 判斷 code 長(zhǎng)度（這里就獲取到條碼值了，以下業(yè)務(wù)自由發(fā)揮）
      	code = $.trim(code)
      if (code.length == 13) {
        this.$message('A類條碼:' + code);
      } else if (code.length == 23) {
				this.$message('B類條碼:' + code);
      } else if (code.length == 0) {
				this.$message('請(qǐng)輸入條碼');
      } else{
      	this.$message('條碼不合法：' + code);
      }
      //鍵入回車務(wù)必清空code值
    	this.code = ''
    	return false;
    }
  }
}

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