Javascript - 使用参数引用全局函数的匿名函数中的闭包 - 我如何使用preventDefault？

Question

In the following code, where would I use preventDefault ? I have been testing it to make it work but have not found a good way to cancel the default submit action. Which function needs to be capture the event object?

Here is the code:

f_name = 'someFunc' ;
f_args(1,2,3) ;

if(element.addEventListener) {
element.addEventListener('submit',(function(name,args,element) {
    return function() {
        window[name].apply(element,args) ;
    }
})(f_name,f_args,element)
,false) ; }

Answer 1

Assuming you want to preventDefault on only some event handlers, you would use preventDefault() inside the callback that you use to handle a specific event. In your example, this would the global function represented by the name argument which would be the someFunc global function.

If you wanted to do it for all event handlers (which doesn't make a lot of sense to me), then you'd do it in your code right before or after you call window[name] .

Answer 2

f_name = 'someFunc';
f_args = [1, 2, 3];
if (element.addEventListener) {
    element.addEventListener('submit', (function (name, args, element) {
        return function (e) {
            // here 
            e.preventDefault();
            window[name].apply(element, args);
        };
    })(f_name, f_args, element), false);
}

Answer 3

Your handler function will be called with the event as a parameter

return function(evt) {
    evt.preventDefault();
    window[name].apply(element,args) ;
}