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I need to use HTML controls (textbox and/or listbox) and want to hide them so the user can't see them. I was wondering how I can set the values of these controls from my CodeBehind area... I have a WebForm DataGrid and in the SelectedIndexChanged I want to write to these HTML controls.
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Doesn't just 'ControlName.Visible = False' work ?

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Also, How can I have my HTML scripts access my WebForm Controls... when their VISIBLE property is set to FALSE?
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If you set an HTML control's Visible property to .F. then .NET simply doesn't generate the relevant HTML

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And, while I'm at it...

I have a JavaScript which I'm using to get the value of a WebForm TextBox Control...
How would I change it to access a WebForm ListBox Control?
I tried what I thought would be right but it didn't like it.

function GetTextBoxValue()
{
	var oTextBox = document.getElementById("txtReminderTime")
	return oTextBox.value
}

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That look OK assuming you have the names right - except a couple of semicolons might help. What do you mean 'it didn't like it' ?
HTH,
Viv