$('#membersearch').keypress(function(e) {
    var membersearchvalue=encodeURIComponent(document.getElementById("membersearch").value)
    if(e.which == 13) {
                var iframe = $('<iframe width="600px" height="500px" style="border:none"></iframe>');
                iframe.attr('src', 'profile.php?username='+membersearchvalue);

                var x = $('$<div title="View Profile"></div>')
                x = iframe.append(x);
                x = x.dialog({ width: 650 });

}