Insert Predefined Text

Inserts predefined text into a text box when the user presses enter or clicks okay
换行
```javascript
// ==UserScript==
// @name         Insert Predefined Text
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Inserts predefined text into a text box when the user presses enter or clicks okay
// @match        *://*/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    // Set the predefined text here
    var predefinedText = "This is the predefined text.";

    // Add an event listener for keydown events
    document.addEventListener('keydown', function(event) {
        // Check if the key pressed was enter
        if (event.key === 'Enter') {
            // Get the active element (the one currently selected by the cursor)
            var activeElement = document.activeElement;

            // Check if the active element is a text box
            if (activeElement.tagName === 'TEXTAREA' || (activeElement.tagName === 'INPUT' && activeElement.type === 'text')) {
                // Insert the predefined text into the text box with a space before it
                activeElement.value += ' ' + predefinedText;
            }
        }
    });
})();
```