I\'m trying to reverse an input string
var oneway = document.getElementById(\'input_field\').value();
var backway = oneway.reverse();
but f
reverse() is a method of array instances. It won't directly work on a string. You should first split the characters of the string into an array, reverse the array and then join back into a string:
var backway = oneway.split("").reverse().join("");
Update
The method above is only safe for "regular" strings. Please see comment by Mathias Bynens below and also his answer for a safe reverse method.