You can use codeingiter's methods base_url() and site_url().
At first, you need to load the URL helper in your controller:
$this->load->helper('url');
See their definitions below (According to CI documentation, http://ellislab.com/codeigniter/user-guide/helpers/url_helper.html)
site_url()
Returns your site URL, as specified in your config file. The index.php
file (or whatever you have set as your site index_page in your config
file) will be added to the URL, as will any URI segments you pass to
the function, and the url_suffix as set in your config file.
You are encouraged to use this function any time you need to generate
a local URL so that your pages become more portable in the event your
URL changes.
Segments can be optionally passed to the function as a string or an
array. Here is a string example:
echo site_url("news/local/123"); The above example would return
something like:
http://example.com/index.php/news/local/123
Here is an example of segments passed as an array:
$segments = array('news', 'local', '123');
echo site_url($segments);
base_url()
Returns your site base URL, as specified in your config file. Example:
echo base_url();
This function returns the same thing as site_url, without the
index_page or url_suffix being appended.
Also like site_url, you can supply segments as a string or an array.
Here is a string example:
echo base_url("blog/post/123");
The above example would return something like:
http://example.com/blog/post/123
This is useful because unlike site_url(), you can supply a string to a
file, such as an image or stylesheet. For example:
echo base_url("/_user_guide_src_ci/images/icons/edit.png");
This would give you something like:
http://example.com/images/icons/edit.png
