/// <summary>Moves the focus to the previous element as defined by tabindex.
/// All elements with an explicit tabindex are defined as being before all
/// elements which don't have an explicit tabindex.</summary>
/// <returns>True if anything happened.</returns>
public bool TabPrevious()
{
// These track the current best found element.
int bestSoFar = int.MaxValue;
HtmlElement best = null;
// Get the current focused element:
HtmlElement focused = htmlActiveElement;
if (focused == null)
{
// Haven't got one - hunt for a node with *no* tabindex first:
body.SearchChildFocusable(null, false, -1, ref bestSoFar, ref best);
if (best == null)
{
// Find the last node with a tabIndex:
body.SearchChildFocusable(null, false, int.MaxValue, ref bestSoFar, ref best);
}
}
else
{
best = focused.GetFocusedPrevious();
}
if (best != null)
{
// Focus it now:
best.focus();
return(true);
}
return(false);
}