Doofinder

Doofinder provides fast, accurate results based on your website contents. Results appear in your search box at an incredible speed as the user types.
Doofinder can be installed in any website with very little configuration.
This extension allows you to easily populate the data Doofinder needs to be able to search your database and to insert the Doofinder layer script into your WordPress site.
With Doofinder you are confident that your visitors are finding what they are looking for.
These are some advantages of using Doofinder in your site:
<ul>
<li>Instant, relevant results.</li>
<li>Tolerant of misspellings.</li>
<li>Search filters.</li>
<li>Increases the conversion rates.</li>
<li>No technical knowledge are required.</li>
<li>Allows the use of labels and synonyms.</li>
<li>Installs in minutes.</li>
<li>Provides statistical information.</li>
<li>Doofinder brings back the control over the searches in your site to you.</li>
</ul>
When users start typing in the search box, Doofinder displays the best results for their search. If users make typos, our algorithms will detect them and will perform the search as if the term were correctly typed.
Furthermore, Doofinder sorts the results displaying the most relevant first.
More info: <a href="http://www.doofinder.com" rel="nofollow ugc">http://www.doofinder.com</a>
<h3>Requirements</h3>
Important: To use this plugin you need to have an account at Doofinder. If you don’t have one you can signup <a href="http://www.doofinder.com/signup" rel="nofollow ugc">here</a> to get your 30 day free trial period.
The minimum technical requirements are basically the same as the WordPress ones. Take a look at their <a href="https://docs.WordPress.com/document/server-requirements/" rel="nofollow ugc">server requirements</a> for more info.
<h3>Configuration</h3>
Once activated, you will see a new entry in the main menu called Doofinder with two sub-menus:
<ul>
<li>Doofinder: To access the main settings page of the module.</li>
</ul>
NOTICE: Doofinder for WordPress has built-in support for <a href="https://wpml.org/es/" rel="nofollow ugc">WPML</a>. In case you are using it, ensure you’ve switched context to one of the defined languages. In All Languages context you won’t be able to configure anything. You will have to configure as many search engines as languages you have in your site.
Doofinder Settings
<h3></h3>
General Settings
<ul>
<li>API Key: This is the secret token you use to index contents (in ML environments you can share the same key). Your API key can be found in the Doofinder Control Panel. Click on your profile name (in the header) and then on API Keys. Make sure you’re using a Management API key and not a Search API key.</li>
<li>Search Engine HashID: Id of the search engine that will index your contents. Can be found in the Doofinder Control Panel. Click on Search Engines in the header. Hash ID will be visible next to the name of your Search Engine. Remember to use different search engines for different languages if you’re in a ML environment.</li>
<li>Update on Save: The period of time that must elapse before the posts / products are updated after making a change.</li>
<li>JS Layer Script: Here you can modify the Layer Javascript Code. It is required for the Javascript Layer to work.</li>
</ul>
<h3>I have any other problem with your plugin. What can I do?</h3>
Just send your questions to <a href="mailto:support@doofinder.com" rel="nofollow ugc">support@doofinder.com</a> and we will try to answer as fast as possible with a working solution for you.

Doofinder WP & WooCommerce Search

This plugin integrates the Doofinder search service with your WordPress site.

jameelbokhari

Awesome Instant Search integrate Instant Search to ANY wordpress website using CSS seletors. If you are familiar with CSS already, you should have no problem setting this up. The less experienced can use <a href="http://www.jameelbokhari.com/awesome-instant-search/" rel="nofollow ugc">my full tutorial</a> to set up in 15-20 minutes.
After installing the plugin, go to Settings->Awesome Instant Search in your admin panel. On the first tab, General Settings, you can activate the plugin, but you should probably set it up first.
If you are working with the TwentyThirteen theme, the plugin should work out of the box. 
TwentyTwelve and TwentyTen can be applied instantly as well. Go to the plugin settings page described above, and under the General Settings use the dropdown next to Theme Quick Settings to select between twentythirteen, twentytwelve and twentyeleven. Again, if you are not using these themes you have to set the plugin up to fit your particular theme. Unfortunately there’s not a way (that I know of) that will get this plugin working out of the box!
For the quick tutorial, see below. For those of you unfamiliar with simple HTML and CSS concepts, <a href="http://www.jameelbokhari.com/awesome-instant-search/" rel="nofollow ugc">see my full tutorial</a>.
<h4>The Essentials</h4>
Essentially, you need to configure three settings.
<ul>
<li>Search Field Selector</li>
<li>Page Content Selector</li>
<li>Search result selector</li>
</ul>
If you know your <code>HTML</code> pretty well, here’s what to do: Assign Search Field Selector to the class or ID of your search field(s) in your website. The default <code>input[name="s"]</code> should work for any website.
Assign Page Content Selector to the ID of the element you want your search results to appear in. Remember to use a period (.) or hash sign (#) just like you would with a <code>CSS</code> selector. So for example <code>#content</code>. Just like with CSS you can be more specific when you need to, e.g., <code>#main #content .container</code> and so on. Keep in mind, this content will be hidden on the current page where the search is performed.
Next, in the same fashion, assign a selector for the search results. In about 99% of websites, this is going to be the same as the content selector with .hentry added in there. For example, if you assigned <code>#content</code> as your Page Content Selector, you would use <code>#content .hentry</code> as your Search Result Selector.
These are the three most important settings. After you get these, go ahead and test it out or play with the other settings.
<h4>Other Settings</h4>
Search URL is where the search results appear. This is your wordpress website’s domain with the letters <code>?=s</code> appended to it — e.g., http://www.example.com?=s 
This shouldn’t need to be changed but is there just in case you ever need to change it.
Hide These Elements If you want additional elements to be hidden when performing a search, use this option. These elements will be revealed again when the search is cleared. This value accepts comma separated <code>CSS</code> selectors, use it to hide comments, page navigation and other extraneous elements when searching.
Before Instant Results is <code>HTML</code> to appear before the Instant Search results. Use the tag %%SEARCH_TERM%% to print the search term, e.g., <code><h3>Search results for: "%%SEARCH_TERM%%"</h3></code> might show up as <code><h3>Search results for: "Contact Info"</h3></code> on your page.
Theme Quick Settings Quickly access default settings for twentyten, twentytwelve, and twentythirteen.
<h4>Translation</h4>
<ul>
<li>Español <a href="http://www.webhostinghub.com/" rel="nofollow ugc">Maria Romos with Web Hosting Hub</a>.</li>
</ul>

Awesome Instant Search

Awesome Instant Search integrate Instant Search to ANY wordpress website.

Doofinder WP & WooCommerce Search vs Awesome Instant Search