How can I check if a string is a float?

Question

I am passing in a parameter called value. I\'d like to know if value is a float. So far, I have the following:

if (!isNaN(value))
{
    alert(\'this is a num         


        

Answer 1

Number.prototype.isFloat = function() {
    return (this % 1 != 0);
}

Then you can

var floatValue = parseFloat("2.13");
var nonFloatValue = parseFloat("11");

console.log(floatValue.isFloat()); // will output true
console.log(nonFloatValue.isFloat()); // will output false

Values like 2.00 cannot really be considered float in JS, or rather every number is a float in JS.

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EDIT: Forgot to mention that extending the prototypes of built-in types is considered a bad parctice (for a good reason) and its use is discouraged in production environments. You could still implement this check as a plain function