Several tests for numbers in JS

JavaScript

function isNumeric(val){
   //return typeof val === 'number' 
   // return parseFloat(val) == val;
   // return isFinite(val) 
   return parseFloat(val) == val && !isNaN(val); 
}

console.log(isNumeric('-1'));
console.log(isNumeric('-1.5'));
console.log(isNumeric('0'));
alert(isNumeric('0.42'));
console.log(isNumeric('.42'));
console.log(isNumeric('99,999'));
alert(isNumeric('0x89f'));
console.log(isNumeric('#abcdef'));
console.log(isNumeric('1.2.3'));
console.log(isNumeric(''));
alert(isNumeric('blah'));