When the controls on the page have the same name and multiple, it is necessary to judge the length from the strict point of the program, and the length and length are two methods of reference.
oele= DOCUMENT.ALL.AAA//There is a AAA object here, but we do not know how long it is now, so there is no way to operate on it. Therefore, we have to do the process of judging length first.
if (oele.length) {}else{};
In both cases, the contents of the curly braces are written differently:
if (oele.length) {
for (var i = 0; i<oele.length;i++) {
Oele[i].value..
}
}
else{
Oele.value..
};
But is it too complicated to write? And when the curly braces inside the code is more, we have to write two times code, dizzy first ~
Okay there
Document.getelementsbyname ()
This method. It is the same with a number of processing, we can use:
Oele = Document.getelementsbyname (' aaa ')
To reference
When the Oele only 1, then is oele[0], there are multiple times, with the subscript method Oele[i] Loop to obtain, is not very simple?
It is worth mentioning that it is equally valid for name and ID. (It can only be applied to the Document object)
<div Id=radiodiv language=javascript >
<input name=radio1 value=1 type= "Radio" >
<input name=radio1 value=0 type= "Radio" checked>
</div>
Document.getelementsbyname ("Radio1"). Item (0). Value result is 1
There is, however, another way to apply a wider range of objects:
getElementsByTagName
<div Id=radiodiv language=javascript >
<input name=radio1 value=1 type= "Radio" id=myradio1>
<input name=radio1 value=0 type= "Radio" Id=myradio2 CHECKED >
</div>
Radiodiv.getelementsbytagname ("Input"). Item (0). Value result is 1
Like I know a <div id= ' aaa ' ><input name=input1 value=1 type=radio ><input name=input1 value=2 type=radio> ......</div> I want to take all the input in the DIV, so I can write it:
Aaa.getelementsbytagname (' INPUT ')
This can be effective and other div (for example, there is a div called BBB, which is the same input) phase difference.
Corresponding to the getElementsByTagName,
There is also a document.body.all.tags ()
The object to use this method is much smaller than the getElementsByTagName. But more than Getelementsbyname.
We're going to have to mention getElementById here.
It is also only the document object to use, and returns the first element of the array, hehe, its method name is getelement rather than getelements
<div Id=radiodiv language=javascript >
<input name=radio1 value=1 type= "Radio" Id=myradio1 >
<input name=radio1 value=0 type= "Radio" Id=myradio2 value= "MyVal2" CHECKED >
</div>
document.getElementById ("MyRadio2"). Value result is MyVal2
