index.html page:

<html>
<head>
<title>Submit Form Demo</title>
</head>
<body>
<form name=”form” method=”post” action=””>

Username:<input type=”text” name=”textfield” id=”textfield” />

<input type=”button” name=”button” name=”button” value=”submit”
onclick=”parent.frames[‘myIframe’].document.frame1.textfield.value=
this.form.textfield.value”/>
</form>
<p>
http://test.html</p>
</body>

</body>
</html>

iframe page : test.html

<!doctype html>
<html lang=”en”>
<head>
<meta charset=”UTF-8″>
<meta name=”Generator” content=”EditPlus®”>
<meta name=”Author” content=””>
<meta name=”Keywords” content=””>
<meta name=”Description” content=””>
<title>Document</title>

</head>
<body>
<form name=”frame1″ method=”post”>
username:<input type=”text” name=”textfield”/>
<!– onchange dont work here–>
</form>
</body>
</html>