<html>
<head>
<title>在指定的时间反复调用函数</title>
</head>
<body onLoad="showtxt()">
<script language="javascript">
<!--
function showtxt(){
a = txt.value;
txt.value = a + "*";
}
setInterval("showtxt()",1000);
//-->
</script>
<input type="text" id="txt">
</body>
</html>