OptinMonster loads jQuery v1.11.3 by default, use this to remove this function. Useful if the site is already loading a different version of jQuery and the page source is outputting multiple copies.
One version for WP users, the other as plain JS.
add_action( 'wp_footer', 'tgm_om_attach_pre' );
function tgm_om_attach_pre() {
?>
<script type="text/javascript">
var om_load_jquery = false;
</script>
<?php
}
<script type="text/javascript">
var om_load_jquery = false;
</script>