                        課程
                    
                        /前端開發
                        
                            /JavaScript
                        
                        /JavaScript入門篇

為什么每個按鈕都沒有起作用呢

<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" Content="text/html; charset=utf-8" />
<title>javascript</title>
<style type="text/css">
body{font-size:12px;}
#txt{
??? height:400px;
??? width:600px;
?border:#333 solid 1px;
?padding:5px;}
p{
?line-height:18px;
?text-indent:2em;}
</style>
</head>
<body>
? <h2 id="con">JavaScript課程</H2>
? <div id="txt">
???? <h5>JavaScript為網頁添加動態效果并實現與用戶交互的功能。</h5>
??????? <p>1. JavaScript入門篇，讓不懂JS的你，快速了解JS。</p>
??????? <p>2. JavaScript進階篇，讓你掌握JS的基礎語法、函數、數組、事件、內置對象、BOM瀏覽器、DOM操作。</p>
??????? <p>3. 學完以上兩門基礎課后，在深入學習JavaScript的變量作用域、事件、對象、運動、cookie、正則表達式、ajax等課程。</p>
? </div>
? <form>
? 
??? <input type="button" value="改變顏色" onlick="set.changeColor()">?
??? <input type="button" value="改變寬高" onlick="set.changeSize()">
??? <input type="button" value="隱藏內容" onlick="set.objHide()">
??? <input type="button" value="顯示內容" onlick="set.objShow()">
??? <input type="button" value="取消設置" onlick="set.offSet()">
? </form>
? <script type="text/javascript">
? var txt=document.getElementById("txt");
? var set=
? {
????? changeColor:function()
????? { txt.style.color="red";
??????? txt.style.backgroundColor="black";
????? },
????? changeSize:function()
????? {
????????? txt.style.width="200px";
????????? txt.style.height="300px";
????? },
????? objHide:function()
????? {
???????? txt.style.display="none";
????? },
????? objShow:function()
????? {
????????? txt.style.display="block";
????? },
????? offSet:function()
????? {
????????? var nocancel=confirm("確認取消設置?");
????????? if(nocancel==true)
????????? {txt.removeAttribute('style'); }
????? }
? }