With Readability it is possible to get information about how easy or difficult your english writings are to read.
Based on specified parameters Readability calculates an average readability of a whole pdf file page but it also gives information about the readability of every sentence.
Especially by adapting the individual parameters it is also possible to create an individual measurement for the readability.

Readability is implemented as a web interface and uses javascript to analize a given text. To use it, simply go to the website .
The startpage requests the user to select a file that he/she wants to be analyzed. With the file chooser the desired file can be selected. Note that only PDF-Files are accepted and this input is necessary to do a readability analysis.
The user can optinally adapt some paramaters to make the analysis more customized to the users needs. For this, he/she has simply to click on "Adapt Parameters" and a panel will appear. With the use of sliders it is possible to adapt the ranges of different parameters. The minimal value indicates that a certain feature below this value is considered to be very easy to read. In contrast, values of a certain feature equal or over a maximal value influences the readability in a negative way. All values between these two values are linearly interpolated to get a smoth transition of the readability score.
Additionally, it is also possible to upload a second PDF-File. This one does not get analyzed but serves as a reference file to extend the basic vocabulary of the analyzation process. Therefore, the text contained in this file gets extracted and the 1000 most frequent used words get extracted and added to a list of the most common used english words. This vocabulary is a indicator of measuring the complexity of a certain word. If a word is in this list, it is classified as very easy to read. If it is not in this vocabulary, it is very difficult to read.
By clicking the button "ANALYZE THE TEXT!" the all the given input data get processed. After all calculations are done the overview page is shown. This perspective visualizes a small preview of every page of the pdf file. Each page contains information about the average values of the calculated features for this page. By clicking on one of the page previews the detailed view is loaded.
The detail view enlarges the selected page so more details about the readability are visible. Every sentence on the page is colored by the average readability value. Additionally, next to the page view each individual sentence is written and the associated calculated readability measures are listed. With this view it is possible to get more information about why a specific sentence is difficult to read.

Note that the implementation was only tested with Google Chrome, Version 59.0

The source code can be found in /app . The basic html code for visualizing the webpage is index.html.txt(we made it a txt extension so you can read the source without the browser rendering it). scripts/main.js contains all the implemented javascript code which also contains the analyzation function and all other necessary stuff. scripts/utilities.js only contains a list with the most common used english words, used by the analyzation function. scripts/ext contains external javascript files. styles contains all CSS-files for altering the appearance of the HTML-elements, whereas styles/main.css is the main style file used by us.
The code documentation of the javascript file main.js can be found in docs/index.html .