扫码枪扫描二维码to值到pc端

最新推荐文章于 2025-01-13 10:56:02 发布

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本文介绍了一种使用JavaScript在JSP页面上监控键盘输入的方法。通过监听onkeypress事件，记录连续按键形成字符串，若两次按键间隔超过100毫秒则清空记录。当按下回车键时，将记录的字符串输出到控制台。

1.jsp中引入

  <script>
                window.onload = function(e) {
                    var code = "";
                    var lastTime, nextTime;
                    var lastCode, nextCode;

                    document.onkeypress = function(e) {
                        nextCode = e.which;
                        nextTime = new Date().getTime();

                        if (lastCode != null && lastTime != null && nextTime - lastTime <= 30) {
                            code += String.fromCharCode(lastCode);
                        } else if (lastCode != null && lastTime != null && nextTime - lastTime > 100) {
                            code = "";
                        }

                        lastCode = nextCode;
                        lastTime = nextTime;
                    }

                    this.onkeypress = function(e) {
                        if (e.which == 13) {
                            console.log(code);
                        }
                    }
                }