Though the next section can be potentially long, it is suggested to go through it for better understanding however it can be skipped without any loss of information.
Back in the 1990's when the World Wide Web was new and the Internet was in its infancy, different companies were in a race to create the best and the most popular browser in order to browse the Internet.
In 1993, the NCSA came up with the first ever graphical web browser named NCSA Mosaic. It helped a lot in expansion and popularizing the World Wide Web.
In 1994, a company called Mosaic Communications was formed which employed many authors of the NCSA Mosaic to create a browser with the aim of dominating the web-browser market. Their product was known as Mosaic Netscape. The company was later renamed as Netscape Communications and the browser was renamed as Netscape Navigator to avoid trademark problems with NCSA.
In 1995, Brendan Eich was recruited by Netscape Communications with the goal of embedding the Scheme programming language into its Netsacpe Navigator, then the most popular web browser. The goal of this job was to create a lightweight and easy to use programming (read scripting) language that can run in the browser environment and is able to generate dynamic content in web pages.
At that time Netscape Communications was already collaborating with Sun Microsystems to include the latter's Java in order to compete with Microsoft for user adoption of its technologies and platforms. So Netscape Communications decided that the new scripting language to be created must complement Java and have similar syntax but not adopt other scripting languages of the time like Perl, Python, TCL or Scheme. Within 10 days, in May 1995, Brendan came up with a working prototype.