--- id: bd7123c9c443eddfaeb5bdef title: Declare JavaScript Variables challengeType: 1 videoUrl: 'https://scrimba.com/c/cNanrHq' forumTopicId: 17556 --- ## Description <section id='description'> In computer science, <dfn>data</dfn> is anything that is meaningful to the computer. JavaScript provides seven different <dfn>data types</dfn> which are <code>undefined</code>, <code>null</code>, <code>boolean</code>, <code>string</code>, <code>symbol</code>, <code>number</code>, and <code>object</code>. For example, computers distinguish between numbers, such as the number <code>12</code>, and <code>strings</code>, such as <code>"12"</code>, <code>"dog"</code>, or <code>"123 cats"</code>, which are collections of characters. Computers can perform mathematical operations on a number, but not on a string. <dfn>Variables</dfn> allow computers to store and manipulate data in a dynamic fashion. They do this by using a "label" to point to the data rather than using the data itself. Any of the seven data types may be stored in a variable. <code>Variables</code> are similar to the x and y variables you use in mathematics, which means they're a simple name to represent the data we want to refer to. Computer <code>variables</code> differ from mathematical variables in that they can store different values at different times. We tell JavaScript to create or <dfn>declare</dfn> a variable by putting the keyword <code>var</code> in front of it, like so: ```js var ourName; ``` creates a <code>variable</code> called <code>ourName</code>. In JavaScript we end statements with semicolons. <code>Variable</code> names can be made up of numbers, letters, and <code>$</code> or <code>_</code>, but may not contain spaces or start with a number. </section> ## Instructions <section id='instructions'> Use the <code>var</code> keyword to create a variable called <code>myName</code>. <strong>Hint</strong><br>Look at the <code>ourName</code> example if you get stuck. </section> ## Tests <section id='tests'> ```yml tests: - text: You should declare <code>myName</code> with the <code>var</code> keyword, ending with a semicolon testString: assert(/var\s+myName\s*;/.test(code)); ``` </section> ## Challenge Seed <section id='challengeSeed'> <div id='js-seed'> ```js // Example var ourName; // Declare myName below this line ``` </div> ### After Test <div id='js-teardown'> ```js if(typeof myName !== "undefined"){(function(v){return v;})(myName);} ``` </div> </section> ## Solution <section id='solution'> ```js var myName; ``` </section>