How do you set the "Visible" property of a ASP.NET control from a Javascript function?

Question

Bascially I want to know the best way to hide/show an ASP.NET control from a Javascript function. I figured I would just access the control in Javascript using:

var theControl = document.getElementById("txtEditBox");

Then just set the control's Visible property to true/false. It doesn't seem to be working, I can't seem to figure out how to set "Visible" to true/false. How can I do that? Also, is that the best way to hide/show a ASP.NET control from a Javascript function?

Thanks, Jeff

Answer 1

The "Visible" property of an ASP.NET control determines whether or not it will be rendered on the client (i.e. sent to the client). If it is false when the page is rendered, it will never arrive at the client.

So, you cannot, technically, set that property of the control.

That said, if the control is rendered on the client because the Visible property is true when the page is rendered, you can then hide it using javascript like this:

var theControl = document.getElementById("txtEditBox");
theControl.style.display = "none";

// to show it again:
theControl.style.display = "";

That assumes that the control's id attribute really is "txtEditBox" on the client and that it is already visible.

Also, is that the best way to hide/show a ASP.NET control from a Javascript function?

There is not necessarily a "best" way, although one better approach is to use CSS class definitions:

.invisible { display: none; }

When you want to hide something, dynamically apply that class to the element; when you want to show it again, remove it. Note, I believe this will only work for elements whose display value starts off as block.