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                        /JavaScript入門篇

為什么我的取消設(shè)置按鈕不起作用

<!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(wǎng)頁添加動(dòng)態(tài)效果并實(shí)現(xiàn)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(jìn)階篇，讓你掌握J(rèn)S的基礎(chǔ)語法、函數(shù)、數(shù)組、事件、內(nèi)置對象、BOM瀏覽器、DOM操作。</p>
????????<p>3.?學(xué)完以上兩門基礎(chǔ)課后，在深入學(xué)習(xí)JavaScript的變量作用域、事件、對象、運(yùn)動(dòng)、cookie、正則表達(dá)式、ajax等課程。</p>
????</div>
????<form>
????????<!--當(dāng)點(diǎn)擊相應(yīng)按鈕，執(zhí)行相應(yīng)操作，為按鈕添加相應(yīng)事件-->
????????<input?type="button"?value="改變顏色"?onClick="setcolor()">
????????<input?type="button"?value="改變寬高"?onClick="sewh()">
????????<input?type="button"?value="隱藏內(nèi)容"?onClick="setyc()">
????????<input?type="button"?value="顯示內(nèi)容"?onClick="setxc()">
????????<input?type="button"?value="取消設(shè)置"?onClick="reset()">
????</form>
????<script?type="text/javascript">
????????//定義"改變顏色"的函數(shù)
????????var?cc?=?document.getElementById("con")
????????var?tt?=?document.getElementById("txt")

????????function?setcolor()?{
????????????cc.style.color?=?"#10e31a";
????????????tt.style.color=?"#09b5ed";
????????}

????????//定義"改變寬高"的函數(shù)
????????function?sewh()?{
????????????cc.style.height?=?"100px";
????????????cc.style.width?=?"300px";
????????????tt.style.height="300px";
????		tt.style.width="400px";

????????}

????????//定義"隱藏內(nèi)容"的函數(shù)
???????function?setyc(){
		???cc.style.display="none";
		???tt.style.display="none";
	???}

????????//定義"顯示內(nèi)容"的函數(shù)
???????????function?setxc(){
		???cc.style.display="block";
		???tt.style.display="block";
		???}
????????//定義"取消設(shè)置"的函數(shù)
		function?reset(){
			var?messages=confirm("你確定要重置嗎？");
			if?(messages==true){
				tt.removeAttribute("style");
			}
		}
????</script>
</body>

</html>