Left Nav Toggle with persistence

Scenario:
While now web is flooded with amazing scripts that can increase user experience, there is always a need to develop something new very specific to your client.

So my client wanted to Toggle left navigation with persistence. Simple script did the magic.

Solution Details:
You can add this script to master page to provide functionality throughout. Two main pieces which drives this are :

1. JavaScript ( to be placed in head tag )
2. HTML control/element to trigger the call to JavaScript function
3. JavaScript ( to be placed at the end of the page, so that it can execute on page load )

JavaScript( this will go in head tag ):

<script type="text/javascript" >

    function getCookie(Name) {
        var re = new RegExp(Name + "=[^;]+", "i"); //construct RE to search for target name/value pair
        if (document.cookie.match(re)) //if cookie found
            return document.cookie.match(re)[0].split("=")[1] //return its value
        return ""
    }

    setCookie = function setCookie(name, value) {
        document.cookie = name + "=" + value + ";path=/" //cookie value is domain wide (path=/)
    }


    function togglefn() {

        var e = document.getElementById('s4-leftpanel');
        var e1 = document.getElementById('MSO_ContentTable');

        if (e.style.display != "none") {
            setCookie('showLeftNav', 'no');
            e.style.display = "none";
            e1.style.marginLeft = "10px";
        }
        else {
            setCookie('showLeftNav', 'yes');
            e.style.display = "block";
            e1.style.marginLeft = "155px";
        }
    }
</script>

HTML element ( some where in body tag):

<a href="javascript:togglefn();">hide/show</a>

JavaScript( this will go towards page end ):

<script type="text/javascript" >
     var persistedLeftNav = getCookie('showLeftNav');

     if (persistedLeftNav == 'undefined') {
         setCookie('showLeftNav', 'yes');
     }
     else {
         if (persistedLeftNav == 'no') {
             togglefn();
         }
     }
</script>