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getElementById will return an object corresponding to the element node that has the given ID attribute value.
<meta http-equiv= "Content-type" content= "text/html; Charset=utf-8 "/>
<title> Untitled Document </title>
<body>
<p title= "A gentle reminder" >don ' t forget to buy this stuff.</p>
<ul id= "Purchase" >
<li>a Tin of Beans</li>
<li class= "Sale" >Cheese</li>
<li class= "Sale Important" >Milk</li>
</ul>
<script>
Alert (typeof document.getElementById ("purchase"));
</script>
</body>
The getElementsByTagName method returns an array of objects, each corresponding to a set of elements in the document that have a given label.
<meta http-equiv= "Content-type" content= "text/html; Charset=utf-8 "/>
<title> Untitled Document </title>
<body>
<p title= "A gentle reminder" >don ' t forget to buy this stuff.</p>
<ul id= "Purchase" >
<li>a Tin of Beans</li>
<li class= "Sale" >Cheese</li>
<li class= "Sale Important" >Milk</li>
</ul>
<script>
For (Var i=0;i<document.getelementsbytagname ("Li"). length;i++) {
Alert (typeof document.getelementsbytagname ("Li") [i]);
}
</script>
</body>
Getelementsbyclassname (HTML5), which takes only one argument, the class name, to return an array of elements with the same class name
<meta http-equiv= "Content-type" content= "text/html; Charset=utf-8 "/>
<title> Untitled Document </title>
<body>
<p title= "A gentle reminder" >don ' t forget to buy this stuff.</p>
<ul id= "Purchase" >
<li>a Tin of Beans</li>
<li class= "Sale" >Cheese</li>
<li class= "Sale Important" >Milk</li>
</ul>
<script>
Alert (Document.getelementsbyclassname ("sale Important"). length);
</script>
</body>
GetAttribute is a function that, by appending the name of a parameter, can get the value of this parameter and the corresponding setattribute can set the name and value of the parameter to be assigned by two parameters.
<meta http-equiv= "Content-type" content= "text/html; Charset=utf-8 "/>
<title> Untitled Document </title>
<body>
<p title= "A gentle reminder" >don ' t forget to buy this stuff.</p>
<ul id= "Purchase" >
<li>a Tin of Beans</li>
<li class= "Sale" >Cheese</li>
<li class= "Sale Important" >Milk</li>
</ul>
<script>
var paras=document.getelementsbytagname ("P");
for (Var i=0;i<paras.length;i++) {
var title_text=paras[i].getattribute ("title");
if (Title_text) {
Paras[i].setattribute ("title", "brand new title text");
Alert (Paras[i].getattribute ("title"));
}
}
</script>
</body>
Five common DOM methods in JavaScript
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