javascript check if number
//Updated dec 2020
// The first 2 Variations return a Boolean
// They just work the opposite way around
// IsInteger
if (Number.isInteger(val)) {
// It is indeed a number
}
// isNaN (is not a number)
if (isNaN(val)) {
// It is not a number
}
// Another option is typeof which return a string
if (typeof(val) === 'number') {
// Guess what, it's a bloody number!
}javascript check if number
function isNumber(n) { return /^-?[\d.]+(?:e-?\d+)?$/.test(n); }
------------------------
isNumber('123'); // true
isNumber('123abc'); // false
isNumber(5); // true
isNumber('q345'); // false
isNumber(null); // false
isNumber(undefined); // false
isNumber(false); // false
isNumber(' '); // falsejavascript check if is nan
function isNaN(x) {
return x !== x;
};
isNaN(NaN);//trueisnan in javascript
var s = userInput[0];
if(isNaN(s) !== true)
{
console.log("yes");
}
else
{
console.log("no");
}Copyright © 2021 Codeinu
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