Hi,
Try it this way
<form action="../">
<select onchange="window.open(this.options[this.selectedIndex].value,'_top')">
<option value="">Select...</option>
<option value="/Index.html">Home</option>
<option value="/collections/all.html">Books</option>
<option value="/blogs/five-simple-steps-blog.html">Blog</option>
<option value="/pages/about-us.html">About Us</option>
<option value="/pages/support.html">Support</option>
</select>
</form>
Hope this works and helps you ! :)
Regards,
Praneet