2023-08-14T14:53:19.png

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>文本框内容拼接示例</title>
</head>
<body>
    <h3>文本框1：</h3>
    <textarea id="text1" rows="6" cols="50"></textarea>
    
    <h3>文本框2：</h3>
    <textarea id="text2" rows="6" cols="50"></textarea>
    
    <h3>文本框3：</h3>
    <textarea id="text3" rows="6" cols="50"></textarea>
    
    <br>
    <button onclick="concatenateText()">点击拼接</button>
    
    <script>
        function concatenateText() {
            var text1 = document.getElementById("text1").value.split('\n');
            var text2 = document.getElementById("text2").value.split('\n');
            var text3 = document.getElementById("text3").value.split('\n');
            
            var result = "";
            var maxLength = Math.max(text1.length, text2.length, text3.length);
            
            for (var i = 0; i < maxLength; i++) {
                if (i < text1.length) {
                    result += text1[i];
                }
                
                if (i < text2.length && text2[i].trim() !== "") {
                    result += text2[i];
                }
                
                if (i < text3.length) {
                    result += text3[i];
                }
                
                result += '\n';
            }
            
            document.getElementById("text1").value = result;
        }
    </script>
</body>
</html>