Website does not work for firefox and explorer IE11

Question

For what do I need to pay attention if I want to my Website to work for all Browsers? I included the following files into my .html, but the firefox does not show my navigation right and in Explorer my overlay which is a section is not right too.

     <!-- HTML5 shiv and Respond.js support IE8 or Older for HTML5 elements 
     and media queries -->
    <!--[if lt IE 9]>
    <script src="https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js">
    <script src="https://oss.maxcdn.com/html5shiv/3.7.3/html5shiv.min.js">
    </script>
    <script src="bower_components/html5shiv/dist/html5shiv.js"></script>
    <script src="bower_components/html5shiv/dist/html5shiv-printshiv.js">
    <![endif]-->

I found out my explorer is the version 11 but I dont find any help for that.

What can I do to include my website for Mozilla firefox and explorer is the main question.

Answer 1

check out this post . I think this is the same problem, if it isn't just leave me a comment.