isNAN function in javascript

isNAN function checks the argument and returns true if the argument is not a number else return false


Example of isNAN()

var val='04cs';

if(isNAN(val))
{
alert('this is not a number') ;
}else{
alert('this is a number') 

}


ANS : this is not a number


var value='0411';

if(isNAN(value))
{
alert('this is not a number') ;
}else{
alert('this is a number') 

}


ANS : this is a number