JavaScript: Check a given value contains alpha, dash and underscore

Last update on May 30 2022 10:01:27 (UTC/GMT +8 hours)

JavaScript validation with regular expression: Exercise-20 with Solution

Write a JavaScript function to check a given value contains alpha, dash and underscore.

Pictorial Presentation:

JavaScript: Check a given value contains alpha, dash and underscore

Sample Solution:-

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JavaScript function to check a given value contains alpha, dash and underscore</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function is_alphaDash(str)
{
 regexp = /^[a-z0-9_\-]+$/i;
  
        if (regexp.test(str))
          {
            return true;
          }
        else
          {
            return false;
          }
}

console.log(is_alphaDash('12-133'));

console.log(is_alphaDash('100_23'));

Sample Output:

true
true

Flowchart:

Live Demo:

See the Pen javascript-regexp-exercise-20 by w3resource (@w3resource) on CodePen.

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Next:Write a JavaScript function to print an integer with commas as thousands separators.

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JavaScript: Tips of the Day

How to insert an item into an array at a specific index (JavaScript)?

What you want is the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert). In this example we will create an array and add an element to it into index 2:

var arr = [];
arr[0] = "Jani";
arr[1] = "Hege";
arr[2] = "Stale";
arr[3] = "Kai Jim";
arr[4] = "Borge";

console.log(arr.join());
arr.splice(2, 0, "Lene");
console.log(arr.join());

Ref: https://bit.ly/2BXbp04