Question

How to check if a variable value is not a number (NaN) in JavaScript

Answer 1

function is_number(n) {  
    if (isNaN(n)) {  
        return "Not a number";  
    }  
    return "A number";  
}  

document.write(is_number(8374) + "<br />");  
document.write(is_number('15') + "<br />");  
document.write(is_number('F16') + "<br />");  


/*
run:
 
A number
A number
Not a number

*/

 

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