title: Understanding Case Sensitivity in Variables
challengeType: 1
---
## Description
<sectionid='description'>
In JavaScript all variables and function names are case sensitive. This means that capitalization matters.
<code>MYVAR</code> is not the same as <code>MyVar</code> nor <code>myvar</code>. It is possible to have multiple distinct variables with the same name but different casing. It is strongly recommended that for the sake of clarity, you <em>do not</em> use this language feature.
<h4>Best Practice</h4>
Write variable names in JavaScript in <dfn>camelCase</dfn>. In <dfn>camelCase</dfn>, multi-word variable names have the first word in lowercase and the first letter of each subsequent word is capitalized.
testString: assert(typeof studlyCapVar !== 'undefined' && studlyCapVar === 10, '<code>studlyCapVar</code> is defined and has a value of <code>10</code>');
testString: assert(typeof properCamelCase !== 'undefined' && properCamelCase === "A String", '<code>properCamelCase</code> is defined and has a value of <code>"A String"</code>');
testString: assert(typeof titleCaseOver !== 'undefined' && titleCaseOver === 9000, '<code>titleCaseOver</code> is defined and has a value of <code>9000</code>');
testString: assert(code.match(/studlyCapVar/g).length === 2, '<code>studlyCapVar</code> should use camelCase in both declaration and assignment sections.');
testString: assert(code.match(/properCamelCase/g).length === 2, '<code>properCamelCase</code> should use camelCase in both declaration and assignment sections.');
testString: assert(code.match(/titleCaseOver/g).length === 2, '<code>titleCaseOver</code> should use camelCase in both declaration and assignment sections.');