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                        /JavaScript入門篇

求解。為何我的點(diǎn)擊沒(méi)有任何響應(yīng)？

<!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(yè)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(yǔ)法、函數(shù)、數(shù)組、事件、內(nèi)置對(duì)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(duì)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="changeColor()">??
????<input?type="button"?value="改變寬高"?onclick="changeSize()">
????<input?type="button"?value="隱藏內(nèi)容"?onclick="toHide()">
????<input?type="button"?value="顯示內(nèi)容"?onclick="toDisplay()">
????<input?type="button"?value="取消設(shè)置"?onclick="cancelSetting()">
??</form>
??<script?type="text/javascript">
??
????var?mychar?=?document.getElementById("txt");
??
//定義"改變顏色"的函數(shù)
????function?changeColor(){
????????mychar.style.color?=?"blue";
????????mychar.style.backgroundColor?=?"#ccc";
????}

????
//定義"改變寬高"的函數(shù)
????function?changeSize(){
????????mychar.style.width?=?"400px";
????????mychar.style.height?=?"600px";
????}

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

//定義"顯示內(nèi)容"的函數(shù)
????function?toDisplay(){
????????mychar.style.display?=?"block";
????}

//定義"取消設(shè)置"的函數(shù)
????function?cancelSetting(){
????????var?a?=?confirm("是否要取消設(shè)置？");
????????if(a?==?true){
????????????mychar.removeAttribute('style'};????????
????????}

????}

??</script>
</body>
</html>