I created browser application and noticed some strange behavior when I tested it on my iPad, which has OS version 9.3.
On Firefox, Chrome, Safari (desktop), and iPad Safari (OS version 9 and below), this problem doesn't happen.
There is an input filed on the page. If I leave the input field blank and press button ”convert” I get an alert for incorrect input. But if I click Page Two, then click the browser's back arrow, and once again press "convert," with the field still empty, I do not get an alert. Nor do I get an alert if I enter a negative number or a letter. However, if I do put a positive number in the field, the currency is converted as usual, which means that the rest of the JavaScript does work, including what happens when correct input is given and the alert portion of the convert() function is the only part malfunctioning.
What's causing this and how would I go about fixing it?