Google CSE Search is based on Custom Search JSON API and Standard Search Element in Custom Web Search which Google described as follows

” Google Custom Search enables you to create a search engine for your website, your blog, or a collection of websites. You can configure your engine to search both web pages and images. You can fine-tune the ranking, add your own promotions and customize the look and feel of the search results. You can monetize the search by connecting your engine to your Google AdSense account. “

Please note that even if “Standard Search Element” is FREE from Google, “Custom Search JSON API” is a paid service and it has only 100 Queries per day limit.

This script uses Google API facilities using PHP to your own web site styled to your own way. Also this has “Standard Search Element” and also “Custom Search JSON API”. Please read the following to read more on Google CSE - Google Custom Search

Features

• Google API based, PHP Script
• Available in Standard Search Element and Custom Search JSON API
• Just Need Google Search Engine ID (CX) and Google API Key
• No Database Required.
• Easy to configure and Edit
• Single Configuration file to have basic settings and functions
• Search inside Wikipedia database and get Knowledge Graph at the Search Page
• Get main thumb image to search results
• Boostrap Based Responsive Design