crinus,
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=windows-1251" />
<link rel="stylesheet" type="text/css" href="style.css" />
<script type="text/javascript">
window.onload=function() {
document.getElementById('myForm').onsubmit = function() { processForm(); return false; }
}
function processForm() {
if (document.getElementById('input1').value=='') { alert('Enter a file name.'); }
else { document.getElementById('I1').src = document.getElementById('input1').value; }
}
</script>
</head>
<body>
<img src="allah.png" alt="enter" />
<form name="adress_bar" method="post" action="#" id="myForm">
<tex><input type="text" size="73" name="input1" id="input1" value="http://javascript.ru"></tex>
<loop> <INPUT TYPE="image" SRC="loop.png" > </loop>
<br><iframe id="I1" width="837" height="800"></iframe>
</body>
</html>