Suppose i have following code in body element
Will google serach bot consider this meta tag for search optimization?
var a=document.createElement("meta");
a.setAttribute("name","description");
a.setAttribute("content","Test website");
var b=document.getElementsByTagName("head")[0];
b.appendChild(a);
Not without you having to change some of the code in your site. This page explains what you have to do to make AJAX pages crawlable.