PDF files are generally classified as data files, and these documents are commonly known as portable document format files. Developed by Adobe Systems, the PDF format was implemented in order to provide wider cross compatibility support for viewing and sharing content across widely used systems. The content of a .pdf document normally consists of text, visual elements like images, charts and tables, annotations, bibliographies, indices, footnotes and endnotes among others. Formatting attributes and page layout specifications can be integrated into the content of a PDF file by accessing the features of widely used PDF authoring and editing applications. The technology behind the PDF format allows the content of these PDF files, when viewed in a computer monitor, to look closely similar to its printed version. As of this writing, popular Web browsers have been implemented with support for viewing PDF documents through certain plugins, and the latest version of Google Chrome can be used to open and view the content of a .pdf file without installing any plugin.