<!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>
??<!--當點擊相應按鈕，執行相應操作，為按鈕添加相應事件-->
????<input?type="button"?value="改變顏色"?onclick="colorab()">??
????<input?type="button"?value="改變寬高"?onclick="tylele()">
????<input?type="button"?value="隱藏內容"?onclick="ddii()">
????<input?type="button"?value="顯示內容"?onclick="ddyy()">
????<input?type="button"?value="取消設置"?onclick="backbar()">
??</form>
??<script?type="text/javascript">
???function?colorab(){var?x1=document.getElementById("txt");x1.style.color="red";x1.style.backgroundColor="#ccc";}
???function?tylele(){var?x1=document.getElementById("txt");x1.style.width="400px";x1.style.height="500px";}???
???function?ddii(){var?x1=document.getElementById("txt");x1.style.display="none";}
???function?ddyy(){var?x1=document.getElementById("txt");x1.style.display="block";}?
???function?backbar(){var?x5=confirm("確定取消所有設置？");
???????if(x5==true)
???????{x1.removeAttribute('style');}
???????else
???????{}
???}
??</script>
</body>
</html>
2016-01-03
function?backbar(){ ????//因為你下面用到的?x1?沒有被定義??所以報錯了 ????var?x1=document.getElementById("txt"); ????var?x5=confirm("確定取消所有設置？"); ????if(x5==true){ ????????x1.removeAttribute('style'); ????}else{ ????} }看注釋
2016-01-03
忘了定義變量了，應該是叫定義變量吧？
2016-01-03
哈哈，找到原因了。