Assuming your blockUI does not work at all, try:
<script type="text/javascript">
$("body").blockUI({ css: {
border: 'none',
padding: '15px',
backgroundColor: '#000',
'-webkit-border-radius': '10px',
'-moz-border-radius': '10px',
opacity: .5,
color: '#fff'
}
});
</script>
Since, you are trying to apply it when the HTML page is being constructed (in progress), accessing the body directly and applying blockUI might work.