In the following example we show a stimulus for six seconds. Then the stimulus disappeares and is replaced by a question.
Technically this is achived using a META-Tag that calls a new page after a specified amount of time.
As an additional stimulus you may add a layered image (123.gif in the example) that shows the elapsing time, displaying numbers from 1 to 6.
<HTML>
<?
if (! $NEXT)
echo "<HEAD>
<META HTTP-EQUIV=Refresh CONTENT=6;URL=$SCRIPT_NAME?NEXT=1>
</HEAD>";
echo "<BODY BGCOLOR=white>
<FORM METHOD=POST ACTION=$SCRIPT_NAME>";
if (! $NEXT) {
echo "Please think a few moments about the following question...
<h4>When was the Yalta Conference?</h4>
a) 4.-11. February 1945<BR>
b) 17. July - 2. August 1945<P>
<IMG SRC=123.gif>\n";
}
if ($NEXT==1) {
echo "The correct answer is...<P>
<INPUT TYPE=SUBMIT NAME=A VALUE=a>
<INPUT TYPE=SUBMIT NAME=A VALUE=b>
<INPUT TYPE=HIDDEN NAME=NEXT VALUE=2>";
};
if ($NEXT==2)
echo "You have chosen ($A)<P>";
?>
</FORM>
</BODY>
</HTML>