Javascript value transfer implementation code between two forms_javascript skills

For example, we create a new form FatherPage.htm:
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Copy the code The code is as follows:

In fact, while opening the subform, we can also assign values ​​to the elements of the subform, because the window.open function will also return a reference to the subform, so FatherPage.htm can be modified to:
XML-Code:

Copy code The code is as follows:

By judging whether the reference of the subform is empty, we can also control it to open only one subform. Form:
XML-Code:

Copy code The code is as follows:

< script type="text/javascript">
var child
function OpenChildWindow()
{
if(!child)
child = window.open('ChildPage.htm');
child.document.getElementById('txtInput').value
=document.getElementById('txtInput').value;
}

That alone is not enough , when closing the child form, the child variable of the parent form must also be cleared, otherwise the child form cannot be reopened after it is opened and then closed:
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Copy code The code is as follows:

< ;input type="text" id="txtInput" />