Using JQuery to add metadata in the Head Tag

Try your code within

<script type="text/javascript"> 
     $(document).ready(function() {
         $("head").append("<meta name=viewport content=width=400, initial-scale=0.45, minimum-    scale=0.45/><link rel=apple-touch-icon href=/images/customIcon.png/><meta name=apple-mobile-web-app-capable content=no /><meta name=apple-mobile-web-app-status-bar-style content=black-translucent /><link rel=apple-touch-icon-precomposed href=/images/customIcon.png/> ");
    });
</script>

Short form of $(document).ready(function() {...}) is:

jQuery(function ($) {
    // Your code
})

This will ensure that you code will execute during onload.