jquery trigger action on focus or click but not both

问题

I have this sample code:

$myTrigger
    .click(function(e){
         alert('click');
    })
    .focus(function(e){
         alert('focus');
         $(this).click()
    })

The intent is that I want something to happen when you click on $myTrigger. If, on the other hand, you tab onto it via the keyboard (ie, focus) I want the exact same thing to happen, so I ask it to click.

The catch is if I click on it, it also focuses. So both alerts are going off.

Is there a way to prevent the focus event from going off when clicking?

UPDATE:

Ajm's comment got me thinking that I'm maybe asking the wrong thing.

Question: Does a click event always also trigger focus in javascript (and/or in jQuery?). Can I assume whenever I want to handle both clicking with the mouse and tabbing-in with the keyboard, the focus() event will handle both?

Or is it dependent on the particular element that I'm attaching the events to? (In this case $myObject happens to be an anchor tag (link).

回答1:

jQuery has a built-in functon for this that's not used all that often called .one()

$mytrigger.one('click focus', function() { alert("event"); });

This will only trigger once, or you can re-bind if you want afterwards.

回答2:

To trigger click() for TAB focus (and prevent click() from being triggered twice when focus comes from a mouse click), I did the following:

$('#item').mousedown(function(){
    $(this).data("mouseDown", true);
});

$('#item').mouseup(function(){
    $(this).removeData("mouseDown");
});

$('#item').focus(function(){
    if (!$(this).data("mouseDown"))
        $(this).click();
});

Does that work good for you?

回答3:

Another option is:

$myTrigger
    .mousedown(function(e) {
        e.preventDefault();  // don't grab focus
    })
    .click(function(e) {
         alert('click');
    })
    .focus(function(e) {
         alert('focus');
         $(this).click()
    });

This will leave the keyboard focus wherever it was before when clicking the button, while still allowing the button to become focused via Tab (or programmatically calling .focus() on it).

回答4:

I ran into a similar problem a while back. I solved it by responding to the first event, and ignoring events for the next 20ms.

Try something like this:

$(document).ready(OnReady);

var okToClick = true;

function OnReady() {
    //Attach to both click and focus events
    $("#item").click(PerformAction).focus(PerformAction);
}

function PerformAction() {
    if (okToClick) {
        okToClick = false;

        // Do something interesting here...

        setTimeout(function() { okToClick = true; }, 20);
    }
}

回答5:

You can use only the focus() method and read this article about events (e) types on JavaScript: http://www.quirksmode.org/js/events_properties.html

To detect what event you got with you mouse or keyboard (to test it), u can use:

if (!e) var e = window.event;
alert(e.type);

回答6:

To prevent focus from being called twice set a variable to tell if the element has focus.

var hasFocus = false;
$('#myTrigger').focusIn(
   function(){
      hasFocus = true;
      //do stuff
   }
);

$('#myTrigger').focusOut(
   function(){
      hasFocus = false;
   }
);

Put all functionality on focus and tell jQuery to set the foucus on the element when it is clicked if you run into a browser which doesn't do that.

$(#myTrigger).click( function(){ if(!hasFocus){$(#myTrigger).focus()}});

来源：https://stackoverflow.com/questions/2458109/jquery-trigger-action-on-focus-or-click-but-not-both

标签

jquery

focus

click