Question

How can i set the maximum number of items to be allowed inside a list box ?

That is if i set the maxsize to 4 and the select list has 4 items then no more value can be inserted !

how to do that ?

[there will be 2 lists, user will be able to move options one to another, but one of them will have the limit]

Answer 1

HTML doesn’t offer facilities for this. You’ve just to add an extra if check in your JS code which moves items from one to other list.

E.g.

if (list.options.length < list.size) {
    // Add item.
} else {
    // Show a warning/error?
}