javascript : Object.isNaN([nanValue])
javascript : Object .isNaN( [nanValue] ) Target: Applicable with any javascript Object Variable that holds numeric value . Description : It checks variable value if it is not a numeric value, NaN or infinity then it return true otherwise false . When nanValue is passed as argument then it convert the value in numeric if it's result is NaN then return nanValue otherwise converted Numeric value. Note: If nanValue is not passed then it return true/false . If nanValue is passed then it convert value in numeric and return either Numeric value or nanValue . another way to check whether variable holds numeric value or Nan or infinity also convert the string to number if conversion failed then it return argument value nanValue Syntax: Object .isNaN( [nanValue] ) return true/false or converted Numeric/nanValue Usase: var obj = 55; obj.isNaN() It return false . var obj = 55/0; ...