JavaScript Reference/Javascript Methods/isNaN
"isNaN()" Example
<html>
<body>
<button onclick="alert(isNaN("12.34"));">isNaN False</button>
<button onclick="alert(isNaN("Hello"));">isNaN True</button>
</body>
</html>
"isNaN()" Syntax, Parameters and Note
Note:
Is the specified string NOT numeric.
Returns true or false.
Syntax:
isNaN(param1)
Parameters:
param1 Required; the string to be evaluated.