//
using mshtml ;
IHTMLDocument2 vDocument =
( IHTMLDocument2 )webBrowser1 . Document . DomDocument;
foreach ( IHTMLElement vElement in vDocument . all)
{
if (vElement . tagName . ToLower() == "input" )
{
IHTMLInputElement vInputElement = ( IHTMLInputElement )vElement;
if (vInputElement . type . ToLower() == "checkbox" )
vInputElement . @checked = true ;
}
}