How to hide Global search for everyone

Hi, 

We want to hide the global search field completely. I have tried various techniques, but none seem to work. Any ideas?

Examples:

This in custom.js file

$(document).ready(function() {
$('#globalSearch').hide();
});

And also this in custom.less
#globalSearch {
display: none !important;
}

No success.
Regards Jörgen