Pages of same website opened in multiple instance of browser should refer to same variable using javascript
<ol>
<li>I have website www.xyz.com and it is having 3 pages a, b and c. </li>
<li>I open one page a in Internet Explorer instance 1 (i.e. www.xyz.com/a )</li>
<li>I open the page b in new IE window instacne 2 (i.e. www.xyz.com/b )</li>
<li>I open the page c in the new tab of IE window instance 3(i.e. www.xyz.com/c)  </li>
</ol>

<p>I need a method using javascript <strong>ONLY</strong>, via which I will be able to refer to a variable which I have defined for the website xyz and all three pages a,b and c will use the same variable. If the variable does not exsist I should be able to create the variable using <strong>javascript</strong>.</p>
