# jsPsych "Hello World" experiment In the long tradition of `hello world` examples, this tutorial creates an experiment that outputs the phrase "Hello World" to the browser. Though useless as an actual experiment, the process is helpful for learning the basics of using the jsPsych library. This tutorial will assume that you know very little about how to set up a web page. ## Step 1: Download the jsPsych library Start by downloading the jsPsych library. The most recent version can always be found on the [GitHub releases page](https://github.com/jodeleeuw/jsPsych/releases). Download either the ZIP or TAR archive of the latest release. ![releasespage](/img/githubreleases.jpg) ## Step 2: Create a folder to store your experiment files Create a folder on your computer to put the experiment files in. Once you've created the folder, open the downloaded archive from step 1, and move the extracted folder (called `jsPsych-4.0.1` if using v4.0.1 of jsPsych) into the experiment folder. Here's what it looks like on a mac: ![folder setup](/img/folder-setup.png) ## Step 3: Create a new HTML file To edit jsPsych code, you'll need a programming-friendly text editor. Some free options are: * [Notepad++](http://notepad-plus-plus.org/) (Windows) * [TextMate](http://macromates.com/) (Mac OSX) * [Atom](https://atom.io) (Windows & Mac OSX) Once you've got a text editor that you like, create a new file in the experiment folder called `experiment.html` ![folder setup](/img/folder-with-html.png) ## Step 4: Add the bare-minimum HTML code There's some basic code that (nearly) all HTML documents have in common. Here's a typical bare-bones HTML document ```html My experiment ``` Add the above code to the experiment.html file and save it. If you then open the file in a web browser, you should see a blank page and the title of the page will be 'My experiment'. ## Step 5: Import the jsPsych library To use jsPsych, add a ` ``` You may also want to import the jsPsych stylesheet, which applies a basic set of visual styles to the experiment to make it visually pleasing. This requires adding a `link` tag to the `` section of the document. ```html My experiment ``` ## Step 6: Use the jspsych-text plugin to print a message For the demo, we want to show some text on the screen. This is exactly what the [jspsych-text plugin]() is designed to do. To use the plugin, we need to load it with a ` ``` Once the plugin is loaded, we can create an experiment using the plugin. To declare a trial that uses the text plugin, we create a JavaScript object with the property `type` equal to `'text'`. Then we can specify the [other parameters of the plugin]() in the same object. To add JavaScript code directly to the webpage we need to add a set of ` ``` Now that we have the trial defined, we just need to tell jsPsych to run an experiment consisting of this trial. This requires using the `jsPsych.init` function and specifying the `experiment_structure` parameter. ```html My experiment ``` Once you've saved the file, open it in a browser. You should see "Hello world!" printed on the screen, and if you press a key on the keyboard, the text should disappear (ending the trial).