Solved

Checking if a string is numeric

Posted on 1999-01-01
4
227 Views
Last Modified: 2006-11-17
Can anyone tell me how to check if a string is numeric? The string I would be checking would only be 2 characters long.

Many thanks

Paul
0
Comment
Question by:paul_skin
  • 2
4 Comments
 
LVL 8

Accepted Solution

by:
jhurst earned 50 total points
ID: 1276250
The length does not matter:

x=parseInt(y);
will set x to the numeric value of the string y, if numeric, if not numeric then x will be set to 'Nan'.
0
 
LVL 4

Expert Comment

by:martinag
ID: 1276251
Use isNaN():
isNan(123) will return false
isNan("123") will return false
isNan("123a") will return true

Martin
0
 
LVL 4

Expert Comment

by:martinag
ID: 1276252
Actually, jhurst's solution works like this:
parseInt(123) will return 123
parseInt("123") will return 123
parseInt("123a") will return 123
parseInt("") will return NaN
parseInt("a") will return NaN

Martin
0
 
LVL 2

Expert Comment

by:UniDyne
ID: 7950864
You need to keep in mind that some implementations (such as Rhino) do not return NaN for parseInt(). In Rhino, parseInt() will still return numbers strings like "123a". isNaN() has worked for me under all JavaScript implementations and appears to be more like what you are looking for.

In Rhino, all of the following statements are true. As you can see, isNaN() is more reliable.

parseInt("123a") == 123
parseInt("234-567") == 234
parseInt("a123") == "NaN"
parseInt("a123") != NaN
isNaN("123a") == true
isNaN("a123") == true
isNaN("234-567") == true
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Disabled form text field 2 22
Jquey and footrable 2 35
JavaScript export function not working in IE 15 35
How to drill down using class name and find the text? 25 32
The task A number given should be formatted for easy reading by separating digits into triads. Format must be made inline via JavaScript, i.e., frameworks / functions are not welcome. So let’s take a number like this “12345678.91¿ and format i…
JavaScript can be used in a browser to change parts of a webpage dynamically. It begins with the following pattern: If condition W is true, do thing X to target Y after event Z. Below are some tips and tricks to help you get started with JavaScript …
The viewer will learn the basics of jQuery, including how to invoke it on a web page. Reference your jQuery libraries: (CODE) Include your new external js/jQuery file: (CODE) Write your first lines of code to setup your site for jQuery.: (CODE)
The viewer will learn the basics of jQuery including how to code hide show and toggles. Reference your jQuery libraries: (CODE) Include your new external js/jQuery file: (CODE) Write your first lines of code to setup your site for jQuery…

911 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

25 Experts available now in Live!

Get 1:1 Help Now