我应该使用哪个HTML事件监听器？

Question

I have a web page that interacts with two servlets and consists therefore of two forms. First form sends data to servlet one to prepare some data to fill drop down menus in the second form depending on the selection. Second form holds four drop down menus which represent different attributes of an object (and interacts with servlet two).

Not all combinations of selections from the drop down menus are valid in step two, therefore I want to show some texts beneath the drop downs to make the user aware of invalid combinations. I used onchange="checkValues()" to generate these texts, which works fine per se. ( onsubmit() later prevents invalid combinations from submitting)

The Problem : Unfortunately, the preset combination is an invalid one. I want to show the texts also, when second form is loaded for the first time. I tried to use onsubmit="checkValues()" in form one, but it has no influence on the texts as the drop down menus (and therefore the values to be checked) are loaded after the submit.

Which event would be more appropriate to cover onchange and the first combination after initialization of the drop downs?

Use an other preset combination is not an option.

Answer 1

The best way to do this would be to wrap your site in a single div and attach a single event listener to that div.

Then you can listen to everything without having to make a ton of different event listeners and slowing down your site. You can tell where it came from by evaluating the ID as long as you set one, of course