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Note: This post is over a year old and so the information contained here might be out of date.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

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