fading out mobile menu while scrolling html website using jquery not happening

  css, html, jquery, menu

i have a website in wordpress, i created a mobile menu using a plugin, there is an option in the plugin to remove or create sticky menu,but whatever the option we click, the menu is sticky only, am trying to remove that sticky property, i tried the following code to fade out the menu on scrolling:

    $(."mob-icon-menu").css("opacity", 1 - $(window).scrollTop() / 50);

but it is not working, this is my url enter link description here

can anyone please tell me how to remove the sticky feature or make the menu hidden while user scrolls the screen, thanks in advance

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