<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>document</title></head><body> <div id="first"> <label>请输入选择器的类型（id/class/tagName）：</label><input type="text" id="type"> </div> <div class="second"> <label>请输入想要查找的具体的id/class/tagName：</label><input type="text" id="input"> </div> <button onclick="dom()">查询</button></body><script> function dom() { let output; let type = document.getElementById("type").value; let input = document.getElementById("input").value; if (type === "id") { output = document.getElementById(input); console.log(output); } else if (type === "class") { output = document.getElementsByClassName(input); console.log(output); } else if (type === "tagname") { output = document.getElementsByTagName(input); console.log(output); } else { console.log("error：输入的内容有误，请检查！") } }</script></html>
