Q1109 What are the differences between setTimeout and setInterval, and where would the use of one would be preferable to the other?

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<script language="JavaScript"><!--
TId = setTimeout(statement,milisecond_to_wait)  (JavaScript 1.0 =. Netscape Navigator 2+ Internet Explorer 3+)
//--></script>

will execute a statement once when the time has run out

<script language="JavaScript"><!--
IId = setInterval(statement,interval_in_miliseconds) (JavaScript 1.2 = Internet Explorer 4 Netscape Navigator 4)
//--></script>

will execute the statement every interval miliseconds.

Both can be cancelled - clearTimeout(TId) and clearInterval(IId).

I would use setTimeout and reuse it in a function to simulate setInterval:

<script language="JavaScript"><!--
function everySecond() {
   // something to do
   setTimeout('everySecond()',1000);
}

everySecond(); // start the funtion
//--></script>