javascript - Determine if conversion from string to 32-bit integer will overflow

Question

Trying to do front-end validation on an HTML input instead of throwing an exception in the Java back-end.

Answer 1

Check whether the number is more than 2147483647.

For example:

if (parseInt(num, 10) > 2147483647)
    //BAD!!!

Answer 2

if ((the_number >> 0) != the_number) {
  // overflow...
}

You still need a server-side check because the client-side may turn off Javascript, etc.

Answer 3

Just check:

if (parseInt(myNumberAsString, 10) > 2147483647) {  alert("Invalid int!"); }