Remedy for variable was used before it was defined from jslint

jslint requires a variable is declared with the keyword var before use it, including the global variables. Otherwise, you will get jslint error such as below

• ‘someVariable’ was used before it was defined
• ‘document’ was used before it was defined
• ‘window’ was used before it was defined
• ‘alert’ was used before it was defined
• ‘console’ was used before it was defined
• ‘require’ was used before it was defined

The remedy for this type of jslint errors is to put this line on top of the js file in a comment for native global variables.

/*global document, window, alert, console, require*/

For custom variable, you just have to declare it with the keyword var before use it.