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Javascript ?? ????: HTML ??? ?? ??

ID? html ?? ????

document.getElementById()

?: 

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title>getElementById</title>	
</head>
<body>
	<h2><a href="ipnx.cn">Javascript DOM</a></h2>
	<p id="sp">php中文網(wǎng)</p>

	<script type="text/javascript">
		var sum = document.getElementById('sp');
		document.write(sum);
	</script>
</body>
</html>

head ??? ???? ?? ??? null? ?????.

?? ?? ????? innerHTML? ???? html ??

?? ??? ??? ?????. 

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title></title>	
</head>
<body>
	<p id="sp">php中文網(wǎng)</p>

	<script type="text/javascript">
		var sum = document.getElementById("sp");
		alert(sum.innerHTML);
	</script>
</body>
</html>

??? ?? php ??? ???? ????, js ??? ???? php ??? ???? ?????.

??? ?? ??? ?? ????. ??? ??? ????. 

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title></title>	
</head>
<body>
	<p id="sp">php中文網(wǎng)</p>

	<script type="text/javascript">
		var sum = document.getElementById("sp");
		sum.innerHTML="玩轉(zhuǎn)javascript";
		alert(sum.innerHTML);
	</script>
</body>
</html>

?? ???, Firebug ??? ???? ?? ??? F12? ????

5.png


?? ???? HTML ?? ??

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title></title>	
</head>
<body>
	<p id="sp">php中文網(wǎng)</p>

	<script type="text/javascript">
		var sum = document.getElementsByTagName("p");
		document.write(sum);
	</script>
</body>
</html>

? ?? ???? ?????. ?? ??? ?????. 

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title></title>	
</head>
<body>
	<p id="sp">php中文網(wǎng)</p>

	<ul>
		<li>1</li>
		<li>2</li>
		<li>3</li>
	</ul>

	<script type="text/javascript">
		var sum=document.getElementsByTagName("li");
		//alert(sum);  //返回一個(gè)數(shù)組集合
		//alert(sum.length);//返回?cái)?shù)組數(shù)量
		//alert(sum[0]);  //返回HTMLLIElement  li的節(jié)點(diǎn)對(duì)象
		//alert(sum.item(0)); //同上，意義一樣
		//alert(sum[0].tagName);  //返回第一個(gè)標(biāo)簽的名字
		alert(sum[0].innerHTML);  //顯示第一個(gè)標(biāo)簽的內(nèi)容
	</script>
</body>
</html>

??? ???????. ?? ?? ??? ???? ??? ??? ????. ??? html??? ? ?? ??? ?? ? ?? ?? ?? ????

??? ??? ????

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title></title>	
</head>
<body>
	<p id="sp">php中文網(wǎng)</p>

	<script type="text/javascript">
		var sum=document.getElementsByTagName("body")[0];
		alert(sum);
	</script>
</body>
</html>

getElementsByName

??? ??? ??? ??? ?? ??? ?????.

?? code: 

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title></title>	
</head>
<body>
		<div name="test">php 中文網(wǎng)</div>

	<script type="text/javascript">
		var sum=document.getElementsByName("test")[0];
		alert(sum);
	</script>
</body>
</html>

IE Firefox? Google Chrome? ???? ?????. Firefox? Google ?? ?? ?????. IE ????? name ??? div ??? ??? ???? IE? ????? ?? ?????. ??? ??? ???? ?

getElementsByClassName

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title></title>	
</head>
<body>
		<div name="test" class="dv">php 中文網(wǎng)</div>

	<script type="text/javascript">
		var sum=document.getElementsByClassName("dv");
		alert(sum);
	</script>
</body>
</html>

? ??? ?????.

????
???? ??
||
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>getElementById</title> </head> <body> <h2><a href="ipnx.cn">Javascript DOM</a></h2> <p id="sp">php中文網(wǎng)</p> <script type="text/javascript"> var sum = document.getElementById('sp'); document.write(sum); </script> </body> </html>