JavaScript - check if string contains only numbers

In this article, we want to show how in JavaScript using simple regular expressions, check if the string contains only numbers.

Example expressions:

1. /^[0-9]+$/
2. /^[0-9]{1,}$/
3. /^\d+$/
4. /^\d{1,}$/ 

For example, we can select the first one, and do some tests with match() function:

// ONLINE-RUNNER:browser;

var expression = /^[0-9]+$/;
var text = '1000500100900';

if (text.match(expression)) {
    console.log('I am number!');
}

Alternative solution

// ONLINE-RUNNER:browser;

var expression = /^[0-9]+$/;
var text = '1000500100900';

if (expression.test(text)) {
    console.log('I am number!');
}

See also

1. JavaScript - integer regular expression