<input type='Button' onclick='click();' value='Кнопка'>
<script language="JavaScript">
function click(){
var q = window.showModalDialog('okno1.php','','dialogHeight:150px;dialogWidth:300px;edge:Raised;center:Yes;help:No;resizable:Yes;status:No');
   if (q != null) {
	document.all.имя.value = q;
	form_1.submit();
   }
}
</script>

<input type="button" onclick="clk()" value="knopka">
<script language="JavaScript"> 
var peremen = window.dialogArguments;
function clk() { 
	window.returnValue = document.all.имя.value;
	window.close();
} 
</script>