Use parseFloat() to try to convert n to a number. Use !Number.isNaN() to check if num is a number.
The following code shows how to use isNan to check if a value is a number. Example <!DOCTYPEhtml><html><head><scripttype="text/javascript">document.writeln(isNaN("blue"));document.writeln(isNaN("123"));</script><!--www.java2s.com--></head><body></body></html> ...
The Number.isFinite() function checks if the variable is a number, but also checks if it's a finite value. Therefore, it returns false on numbers that are NaN, Infinity or -Infinity. Let's test it out on the variables we've defined above: > Number.isFinite(intVar); true > Number...
Enter a number: 5 The number is odd. Also Read: Javascript Program to Check if a number is Positive, Negative, or Zero JavaScript Program to Check if a Number is Float or IntegerBefore we wrap up, let’s put your knowledge of Javascript Program to Check if a Number is Odd or Even...
In JavaScript, a value can either be a primitive or an object. Therefore, you can check if a value is a JavaScript primitive (as opposed to being an object) using the following check: !(value instanceof Object) You may see value !== Object(value) as a means to check for prim...
Check if a Value IsNaNby Using a Comparison Operator in JavaScript The following method is even faster than the ones detailed above, and it also requires less code. On the other hand, it is a bit more confusing, not to mention that it may prove to be hard to maintain and document prop...
To check the value for percentage, use a regular expression. When dealing with user input or processing data in JavaScript, it's important to make sure a value is a valid percentage. This article shows you how to check if a value is a percentage using JavaScript, highlighting a useful ...
Alternatively, it can also be used astypeof()methodin JavaScript. Syntax: typeof(variable); Example 1: str="This is my place.";if(typeofstr==String){console.log('The variable is a String.');}else{console.log('The variable is not a String.');} ...
If the char value does not match the regular expression, a false value will be returned. Here is what the method would look like inside a function: JavaScript Copy function isCharacterALetter(char) { return (/[a-zA-Z]/).test(char) } This method will work for characters in the ...
In this article, we will see how to check if a number is between two values in JavaScript. We will be using the comparison operator and the logical operators to achieve this.We can use these operators either with the if statement or the ternary operator ?: in JavaScript....