Weird array of numbers and letters in HTML

Question

I keep getting this output in my web page's page source

<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="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" />

I have no idea what it is?

Answer 1

It is the ASP.NET viewstate. This is how ASP.NET tracks what values and properties your form items have. From Microsoft :

Microsoft® ASP.NET view state, in a nutshell, is the technique used by an ASP.NET Web page to persist changes to the state of a Web Form across postbacks.

Answer 2

That's the viewstate for the controls on your page, they fill it with data that's needed on postback.

If your page doesn't postback you can disable the viewtstate by settting:

EnableViewState = false; for the controls on your page.

Answer 3

It's an ASP.net mechanic to store data/info/values:

Microsoft® ASP.NET view state, in a nutshell, is the technique used by an ASP.NET Web page to persist changes to the state of a Web Form across postbacks.

http://msdn.microsoft.com/en-us/library/ms972976.aspx

Answer 4

This is nothing to worry about.

Have a look at the following for more information:

Understanding ASP.NET View State