(4.17) The difference between getelementbyid,getelementsbyname,getelementsbytagname

<form>    <inputtype= "checkbox"name= "Hobby"ID= "Hobby1"/>Music<inputtype= "checkbox"name= "Hobby"ID= "Hobby2"/>Mountaineering<inputtype= "checkbox"name= "Hobby"ID= "Hobby3"/>Swimming<inputtype= "checkbox"name= "Hobby"ID= "Hobby4"/>Read<inputtype= "checkbox"name= "Hobby"ID= "Hobby5"/>Play<inputtype= "checkbox"name= "Hobby"ID= "Hobby6"/>Running<BR/>    <inputtype= "button"value= "Select All"onclick= "Checkall ()"/>    <inputtype= "button"value= "All is not selected"onclick= "ClearAll ()"/>    <P>Select your preference number, number 1-6</P>    <inputtype= "text"name= "WB"ID= "WB"/>    <inputtype= "button"value= "OK"onclick= "Checkone ()"/>    </form>

<script type= "Text/javascript" >//All selected FunctionsfunctionCheckall () {varHobby = document.getElementsByTagName ("Input");  for(vari=0;i)    {        if(hobby[i].type== "checkbox") {hobby[i].checked=true; }    }}//All-Unchecked functionsfunctionClearAll () {varHobby = Document.getelementsbyname ("Hobby");  for(vari=0;i) {hobby[i].checked=false; }}//Select the selected Radio boxfunctionCheckone () {varJ=document.getelementbyid ("WB"). Value; varHobby=document.getelementbyid ("hobby" +j); Hobby.checked=true;}</script>

Conclusion:

By example, people can identify the identity of the identity card, have the name, there are categories (adults, children, the elderly) and so on.

1. ID is a person's identity card number, is unique. So by getElementById get a designated person.

2. Name is his name and can be repeated. So get a collection of people with the same name by Getelementsbyname.

3. TagName can appear to be a class, getElementsByTagName get the same class of people collection. getElementsByTagName ("Children"), such as children, are available.

(4.17) The difference between getelementbyid,getelementsbyname,getelementsbytagname