This plugin allows your visitors to easily install the search bar of your site in their browser. The plugin also allowsyou to customize the search bar
Activate the plugin, then simply go the Presentation > Widgets section and drag over the Search Button for browser Widget.You can easily customize the widget by entering the URL of an image that you want to show to your visitors for install the search bar in their browser.
Activate the plugin, then go to the Settings > Search Browser and configure the plugin options. After press on "Update Option" button you can find the php code to integrate the plugin in your theme.