checked attribute | checked property (Internet Explorer)

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checked attribute | checked property

[This documentation is preliminary and is subject to change.]

Sets or retrieves the state of the check box or radio button.

Syntax

HTML	`<element checked="p" ... >`
JavaScript	`p = object.checked`

Property values

Type: Boolean

false: Default. Control is not selected.
true: Control is selected.

Standards information

Document Object Model (DOM) Level 1 Specification, Section 2.5.5
HTML 4.01 Specification, Section 17.4

Remarks

Check boxes that are not selected do not return their values when the form is submitted.

A user can select a radio button only if the button has a name. To clear a selected radio button, a user must select another button in the set.

Windows Internet Explorer 8 and later. In IE8 Standards mode, parsing operations on the checked content attribute always affect both the checked content attribute and defaultChecked Document Object Model (DOM) attribute. For example, removeAttribute('checked') sets both checked and defaultChecked to false. Similarly, setAttribute('checked', 'checked') sets both DOM attributes to true (as if the element was being re-parsed) For more information on IE8 mode, see Defining Document Compatibility.

Internet Explorer 8 and later. In IE8 mode, the defaultChecked DOM attribute reflects the value of the checked content attribute.

Examples

This example retrieves the checked property to fire an event.

Code example: http://samples.msdn.microsoft.com/workshop/samples/author/dhtml/refs/checked.htm


<head>
    <script>
    function checkthis()
    {
        if (oCheckbox.checked == true)
        {
            window.open("http://www.microsoft.com");
        }
    }
    </script>
</head>
<body>
    <p>Check here if you wish to go to Microsoft:
    <input id="oCheckbox" type="checkbox" onclick="checkthis()"></p>
</body>

In order to programmatically change a checkbox from checked to not checked, or vice versa, you may need to make it into an object.
To make the checkbox into an object, you need to iterate through "elements" using the "getElementsByTagName method" to find the name you gave your checkbox.
See e.g., http://msdn.microsoft.com/en-us/library/ms762212(v=VS.85).aspx

Here's some code I put together using the getElementsByTagName method

'*''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'* BEGIN_Sub '*' BEGIN_Sub '*' BEGIN_Sub '*' BEGIN_Sub '*' BEGIN_Sub '*' BEGIN_Sub '*' BEGIN_Sub '*' BEGIN_Sub '*' BEGIN_Sub '*' BEGIN_Sub '*'
'*''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Sub subCopyTheArgFileToDir(strDirTargete_namChkBoxe)'(strDirTargete, namChkBoxe)
'
'The following commented lines appear  as a checkbox input element in the body of an Hta I'm using.
'  The checkbox's "onclick" event calls this sub, which copies a file and unchecks the checkbox.
'
'<span id=idSpanrow2_col2>
' <input type="checkbox"
    '  name="namCheckBoxRow2_col2"
    '  id=idCheckBoxRow2_col2
    '  value="1"
    '  onclick="subCopyTheArgFileToDir('ItWorks_vbs,namCheckBoxRow2_col2')">
'</span>
'
Dim strDirTarget_namChkBox
Dim strDirTarget
Dim strNamChkBox

strDirTarget_namChkBox = strDirTargete_namChkBoxe

Dim colChkElem
Set colChkElem = window.document.getElementsByTagName("input")
Dim objChkBox

Dim arChkBoxOnClickArgs
'Split(expression[, delimiter[, count[, compare]]])
arChkBoxOnClickArgs = Split(strDirTarget_namChkBox, ",", 2, vbTextCompare)

strDirTarget = arChkBoxOnClickArgs(0)
strNamChkBox = arChkBoxOnClickArgs(1)

strMsgBoxMsg = strMsgSrcFileName & vbCrLf & _
  "Line No. 91  " & vbCrLf & _
  "strDirTarget  =  " & strDirTarget & vbCrLf & _
  "strNamChkBox  =  " & namChkBox & vbCrLf '& _
  '"XX  =  " & XX & vbCrLf & _
  '"XX  =  " & XX & vbCrLf & _
  '"XX  =  " & XX & vbCrLf & _
  '"XX  =  " & XX & vbCrLf & _
  '"XX  =  " & XX '& vbCrLf & _
MsgBox strMsgBoxMsg
Dim objFSO
Set objFSO=CreateObject("Scripting.FileSystemObject")

Select Case strDirTarget

     Case UCase("ItWorks_Hta")
           strDirTarget = strP_drv_HTA_ItWorksDir ' This is a public variable, containing a path to a folder on my server

    Case UCase("ItWorks_vbs")
           strDirTarget = strP_drv_VBS_ItWorksDir' This is a public variable, containing a path to a folder on my server

  Case Else

End Select ' 'Select Case strDirTarget

If Len(strDirTarget) > 0 Then
    If objFSO.FileExists(strFileInArgFULLName) Then
        objFSO.CopyFile strFileInArgFULLName, strDirTarget
    End If
End If

For Each objChkBox In colChkElem
  If objChkBox.Type = "checkbox" Then
         'MsgBox "checkbox found"

         If objChkBox.checked Then
            Msgbox objChkBox.value & vbCrLf & objChkBox.name

            If StrComp(strNamChkBox, objChkBox.name, vbTextCompare) = 0 Then ' 0 = identical matches
                objChkBox.checked=False ' This changes the setting from checked to not-checked
            End If '

      End If  'If objChkBox.checked Then

  End If 'If objChkBox.Type = "checkbox" Then

Next
'namChkBox.checked=False

End Sub ' subCopyTheArgFileToDir(strArge)
'*''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'* END_Sub '*' END_Sub '*' END_Sub '*' END_Sub '*' END_Sub '*' END_Sub '*' END_Sub '*' END_Sub '*' END_Sub '*' END_Sub '*' END_Sub '*' END_Sub
'*''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''