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V. Basic JavaScript &dom (ii)

Source: Internet
Author: User
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Note Contents Map:

Elements object (Element object)

  • To manipulate the element object, first obtain the element (obtained using the corresponding method in document)
  • The method inside the element
    • GetAttribute ("Property name"): Gets the value inside the property
      <HTML><Body>        <inputtype= "text"ID= "a"class= "haha"value= "Name"></Body>    <Scripttype= "Text/javascript">       varINPUT1=document.getElementById ("a");   alert (Input1.value); //namealert (Input1.getattribute ("value")); //namealert (Input1.class); //Undefined Note: Class is not worth the reason: class is a keyword. So you can only use GetAttribute to take class values.alert (Input1.getattribute ("class")); //hahaalert (input1.id); //aalert (Input1.getattribute ("ID")); //a</Script></HTML>
    • SetAttribute ("name", "value"): Setting properties
    • Removeattribut (name): Delete attribute
      <HTML><Body>        <inputtype= "text"ID= "a"value= "Name"></Body>    <Scripttype= "Text/javascript">       varINPUT1=document.getElementById ("a"); Alert (Input1.getattribute ("class")); //NULLInput1.setattribute ("class","haha"); //set the Class property and give the value hahaalert (Input1.getattribute ("class")); //hahaInput1.removeattribute ("class"); //Delete Attribute classalert (Input1.getattribute ("class")); //NULLInput1.removeattribute ("value"); //Delete property valuealert (Input1.getattribute ("value")); //Name Note: removeattribute cannot delete value! </Script></HTML>
  • Get the sub-label below the label
    • Use attribute ChildNodes, but this property is poorly compatible
      html><Body>        <ulID= "Ulid">        <Li>Aaaa</Li>        <Li>bbbb</Li>        <Li>Cccc</Li>    </ul></Body>    <Scripttype= "Text/javascript">       varUl11=document.getElementById ("Ulid"); varLis=Ul11.childnodes; alert (lis.length); //Under ie the result is 3, under Firefox is 7</Script></HTML>

    • So, the only effective way to get a label on the face tag is to use the getElementsByTagName method. The method return value is a collection

      <HTML><Body>        <ulID= "Ulid">        <Li>Aaaa</Li>        <Li>bbbb</Li>        <Li>Cccc</Li>    </ul></Body>    <Scripttype= "Text/javascript">       varUl11=document.getElementById ("Ulid"); varLis=Ul11.getelementsbytagname ("Li"); alert (lis.length); //3</Script></HTML>

Second, Node object

V. Basic JavaScript &dom (ii)

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