I\'m hoping there\'s something in the same conceptual space as the old VB6 IsNumeric() function?
IsNumeric()
And you could go the RegExp-way:
var num = "987238"; if(num.match(/^-?\d+$/)){ //valid integer (positive or negative) }else if(num.match(/^\d+\.\d+$/)){ //valid float }else{ //not valid number }