you can use by javascript
<script type="text/javascript">
function pop(form) {
var get=document.getElementById('dst1').value;
window.open('admin.php?dst='+get, 'formpopup', 'width=400,height=800,resizeable,scrollbars');
form.target = 'formpopup';
}
</script>
<form name="form" method="post">
<input type="text" name="dst1" id="dst1" value="">
<input type="submit" name="sub1" id="sub1" value="View"
onClick="pop(this);">
</form>