在JS/jQuery中触发一个按键/下键/上键事件

在这篇文章中，我们将讨论在网络技术中使用vanilla JavaScript和Jquery来记录按键的两种方法。我们还将讨论与JavaScript中的按键有关的事件。首先，我们必须创建一个结构，所以让我们先做一个HTML和CSS布局。

HTML和CSS布局：在给定的布局中，当在字段中进行输入时，keyCode值将被记录在框中。
与按键有关的事件如下:

keydown。当一个键被按下时，该事件被触发。
key。当一个键被按下时，该事件被触发。这个事件不能识别Tab、Shift、ctrl、backspace等键。
keyup : 当一个键被释放时，该事件被触发。

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <meta name="viewport" 
              content="width=device-width, initial-scale=1.0" />
        <title>Document</title>
  
        <style>
        h1 {
            color: green;
        }
        .display {
            border: 2px solid black;
            height: 100px;
            width: 400px;
            text-align: center;
        }
  
        .input {
            display: flex;
            flex-direction: column;
            font-size: 0px;
        }
        button {
            border: none;
            margin: 2px;
            width: 80px;
            height: 3vw;
            float: right;
            background-color: green;
            color: white;
        }
        button:hover {
            background-color: rgb(5, 94, 12);
        }
    </style>
    </head>
    <body>
        <h1>GeeksforGeeks</h1>
        <div class="display"><h3></h3></div>
        <div class="input">
            <button>emit event</button>
        </div>
    </body>
</html>

输出:
在JS/jQuery中触发一个按键/下键/上键事件

我们将使用2种方法在JS/jQuery中实现触发按键/下键/上键事件。

使用Vanilla JavaScript。我们将使用本地的dispatchEvent来创建键盘事件，如下所示。

我们给按钮添加一个事件监听器，以触发一系列的事件，在我们创建的显示分区中显示’Hey Geek’。为此我们使用了dispatchEvent(new KeyboardEvent(…))。KeyboardEvent是一个构造函数，它接受一个事件和一个事件属性对象作为参数。

window.addEventListener('load', ()=>{
    document.querySelector('button').addEventListener('click', ()=>{
        document.dispatchEvent(new KeyboardEvent('keypress', {'key': 'H'}));
        document.dispatchEvent(new KeyboardEvent('keypress', {'key': 'e'}));
        document.dispatchEvent(new KeyboardEvent('keypress', {'key': 'y'}));
        document.dispatchEvent(new KeyboardEvent('keypress', {'key': ' '}));
        document.dispatchEvent(new KeyboardEvent('keypress', {'key': 'G'}));
        document.dispatchEvent(new KeyboardEvent('keypress', {'key': 'e'}));
        document.dispatchEvent(new KeyboardEvent('keypress', {'key': 'e'}));
        document.dispatchEvent(new KeyboardEvent('keypress', {'key': 'k'}));
    });
});
document.addEventListener('keypress', (event)=>{
    document.querySelector('h1').innerHTML += event.key;
});

使用jQuery。我们首先创建一个事件e，并将key属性分配给它，如上述代码所示。使用Jquery.trigger(e)，我们发出事件，并以与方法1中相同的方式处理它。然而，我们没有使用innerHTML，而是使用Jquery的.append()方法。

$(document).ready(()=>{
    $('button').on('click', ()=>{
        let e = $.Event('keypress');
        e.key = 'H';
        $(document).trigger(e);
        e.key = 'e';
        $(document).trigger(e);
        e.key = 'y';
        $(document).trigger(e);
        e.key = ' ';
        $(document).trigger(e);
        e.key = 'G';
        $(document).trigger(e);
        e.key = 'e';
        $(document).trigger(e);
        e.key = 'e';
        $(document).trigger(e);
        e.key = 'k';
        $(document).trigger(e);
          
    })
});
$(document).on('keypress', (event)=>{
      
    $('h1').append(event.key);
})

最终解决方案：我们将简单地使用本代码中的方法1，你可以使用其中任何一种方法，如下所示。

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <meta name="viewport" 
              content="width=device-width, initial-scale=1.0" />
        <title>Document</title>
        <script src="https://code.jquery.com/jquery-3.5.0.slim.js" 
                integrity="sha256-sCexhaKpAfuqulKjtSY7V9H7QT0TCN90H+Y5NlmqOUE="
                crossorigin="anonymous">
        </script>
            <style>
        h1 {
            color: green;
        }
        .display {
            border: 2px solid black;
            height: 100px;
            width: 400px;
            text-align: center;
        }
  
        .input {
            display: flex;
            flex-direction: column;
            font-size: 0px;
        }
        button {
            border: none;
            margin: 2px;
            width: 80px;
            height: 3vw;
            float: right;
            background-color: green;
            color: white;
        }
        button:hover {
            background-color: rgb(5, 94, 12);
        }
    </style>
    </head>
    <body>
        <h1>GeeksforGeeks</h1>
        <div class="display"><h3></h3></div>
        <div class="input">
            <button>emit event</button>
        </div>
        <script type="text/javascript">
            window.addEventListener("load", () => {
                document.querySelector("button").addEventListener("click", () => {
                    document.dispatchEvent(new KeyboardEvent("keypress", { key: "H" }));
                    document.dispatchEvent(new KeyboardEvent("keypress", { key: "e" }));
                    document.dispatchEvent(new KeyboardEvent("keypress", { key: "y" }));
                    document.dispatchEvent(new KeyboardEvent("keypress", { key: " " }));
                    document.dispatchEvent(new KeyboardEvent("keypress", { key: "G" }));
                    document.dispatchEvent(new KeyboardEvent("keypress", { key: "e" }));
                    document.dispatchEvent(new KeyboardEvent("keypress", { key: "e" }));
                    document.dispatchEvent(new KeyboardEvent("keypress", { key: "k" }));
                });
            });
  
            document.addEventListener("keypress", (event) => {
                document.querySelector("h3").innerHTML += event.key;
            });
        </script>
    </body>
</html>

输出:

在JS/jQuery中触发一个按键/下键/上键事件