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JavaScript JavaScript Basics (Retired) Working With Numbers Numbers and Strings

Richard Hummel
PLUS
Richard Hummel
Courses Plus Student 5,677 Points
Posted by Richard Hummel
Richard Hummel
Courses Plus Student 5,677 Points

parseInt not giving me correct value

I'm not sure what I'm doing wrong in my syntax in the app.js file.

app.js 
var width = '190px';
var numOfDivs = 10;
parseInt(width);
var totalWidth = width * numOfDivs;
index.html 
<!DOCTYPE HTML>
<html>
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  <title>JavaScript Basics</title>
</head>
<body>
<script src="app.js"></script>
</body>
</html>

1 Answer

Michael Davidson
Michael Davidson
5,519 Points
Michael Davidson
Michael Davidson
5,519 Points

Okay so what you've done looks like it makes sense, but there is a problem.

Your javascript:

var width = '190px';
var numOfDivs = 10;
parseInt(width);
var totalWidth = width * numOfDivs;

While you did parseInt(width) in there, you never set width = parseInt(width) so it doesn't change your variable. So your final call takes the string '190px' and says NAN

If you do 

var width = '190px';
document.write(width + ' <br>');
width = parseInt(width)
var numOfDivs = 10;
document.write(width + ' <br>');
var totalWidth = width * numOfDivs; 
document.write(totalWidth);

Your document will output

190px 190 1900

Because when you change the variable to the parse int, you assign that as what you're working with :)

[Mod Note - Changed to answer instead of comment so this can be voted on or marked as best answer.]

Richard Hummel
Richard Hummel
Courses Plus Student 5,677 Points
Richard Hummel
Richard Hummel
Courses Plus Student 5,677 Points

OK so I'm essentially reassigning the 'width' variable to the value of the parseInt. Thanks.