JavaScript Function isNaN

24th December 2007 - 1 minute read time

Note: This post is over a year old and so the information contained here might be out of date. If you do spot something please leave a comment and we will endeavour to correct.

Small JavaScript function to check if a variable is a number.

function checkValue(value){
  if(isNaN(value)){
    return false;
  }else{
    return true;
  }
}

Use this in your form validation if you are checking to see that a user has entered a number.

JavaScript

Add new comment

Related Content

Vissles V84 Wireless Mechanical Keyboard: A Review

I recently acquired a Vissles V84 mechanical keyboard and I have spent some time giving it a go. Vissles was founded in 2018 and have a selection of decent looking accessories and devices including wireless chargers, headphones and monitors. The V84 is the second of keyboard that Vissles have created, iterating on the previous design.

Failed Web Predictions And How Not To Talk To Web Developers

Picture the scene, it's 2010, you're a young web developer working in a satellite office of a fast paced digital agency. The work is interesting, but normally quite stressful as there are tight deadlines and high expectations on delivering good work. There is a lot going on so you tend to finish one website and jump onto the next. The company you work for has a history of firing people and making people redundant, especially in the satellite office you work at.

Using Shadow DOM

When I first heard the term "Shadow DOM" I had to laugh at the name. I had visions of a cloak and dagger HTML element that would only be seen on the dark web. Or some sort of nefarious shadow site that was the after effect of a hack. In reality, this is quite a useful bit of technology that has a number of applications, although it does need a fairly modern browser to be able to use it. Shadow DOM is part of the web components strategy, which includes custom elements and HTML templates. These give developers the power to create custom tools and experiences that are encapsulated away from other parts of the code. In this article I will go though what the shadow DOM is, how to use it, and in what situations it comes in handy.

Simple Horizontal Segmented Bar Chart With CSS

Bar charts are powerful ways to show the relationships between different data items. If the data you want to show is discrete then a simple horizontal segmented bar chart is a good idea. You can easily change a collection of numbers into a related set of attributes.

Inspecting And Reusing jQuery Events

Adding events to HTML elements with jQuery is pretty simple, but I found that extending those events wasn't an easy task. I was faced with an issue where I had some third party code that performed an action on an element, and I needed to add an event and call the same handler from that event. As this was within a CMS I had limited scope to just add my new event to the existing code, so I needed a way of pulling out the current jQuery events and then calling that event handler separately. This post looks at how I accomplished this.

Keychron K2 Wireless Mechanical Keyboard: A Review

I (like a lot of other people) recently started to work at home a lot more, and with a permanent desk setup at home I wanted a decent keyboard to work with. My work machine is a MacBook Pro 2018 and I dislike the keyboard quite a lot. It feels 'poppy', has some interesting key placements (the up and down arrows in particular), has no escape key or function keys at all.