ASP.NET

<input type="textbox" ....>
<input type="chekbox" ....>
<input type="button" ....>

<asp:textbox...> or <asp:checkbox...>

function DisableAllControls()
{
    var arrControls = document.getElementByTagName('input') 
    // since we are trying to gather all controls having <input> tag 
    // returns an array of control's ID ..so each array
    // element is a control of your page.
        
    for(int i=0;iterate upto arrControls.length)
    {
        arrControls[i].disabled = true;
    }
    // setting each control's 'disabled' property to true
    // to disable all the control.
}