虽然它不是一个完美的解决方案,但以下是我们用来在包含 Select2 元素的 HTML 表单上模拟普通键盘导航的方法。
/**
* WARNING: untested using Select2's option ['selectOnClose'=>true]
*
* This code was written because the Select2 widget does not handle
* tabbing from one form field to another. The desired behavior is that
* the user can use [Enter] to select a value from Select2 and [Tab] to move
* to the next field on the form.
*
* The following code moves focus to the next form field when a Select2 'close'
* event is triggered. If the next form field is a Select2 widget, the widget
* is opened automatically.
*
* Users that click elsewhere on the document will cause the active Select2
* widget to close. To prevent the code from overriding the user's focus choice
* a flag is added to each element that the users clicks on. If the flag is
* active, then the automatic focus script does not happen.
*
* To prevent conflicts with multiple Select2 widgets opening at once, a second
* flag is used to indicate the open status of a Select2 widget. It was
* necessary to use a flag instead of reading the class '--open' because using the
* class '--open' as an indicator flag caused timing/bubbling issues.
*
* To simulate a Shift+Tab event, a flag is recorded every time the shift key
* is pressed.
*/
jQuery(document).ready(function($) {
var docBody = $(document.body);
var shiftPressed = false;
var clickedOutside = false;
//var keyPressed = 0;
docBody.on('keydown', function(e) {
var keyCaptured = (e.keyCode ? e.keyCode : e.which);
//shiftPressed = keyCaptured == 16 ? true : false;
if (keyCaptured == 16) { shiftPressed = true; }
});
docBody.on('keyup', function(e) {
var keyCaptured = (e.keyCode ? e.keyCode : e.which);
//shiftPressed = keyCaptured == 16 ? true : false;
if (keyCaptured == 16) { shiftPressed = false; }
});
docBody.on('mousedown', function(e){
// remove other focused references
clickedOutside = false;
// record focus
if ($(e.target).is('[class*="select2"]')!=true) {
clickedOutside = true;
}
});
docBody.on('select2:opening', function(e) {
// this element has focus, remove other flags
clickedOutside = false;
// flag this Select2 as open
$(e.target).attr('data-s2open', 1);
});
docBody.on('select2:closing', function(e) {
// remove flag as Select2 is now closed
$(e.target).removeAttr('data-s2open');
});
docBody.on('select2:close', function(e) {
var elSelect = $(e.target);
elSelect.removeAttr('data-s2open');
var currentForm = elSelect.closest('form');
var othersOpen = currentForm.has('[data-s2open]').length;
if (othersOpen == 0 && clickedOutside==false) {
/* Find all inputs on the current form that would normally not be focus`able:
* - includes hidden <select> elements whose parents are visible (Select2)
* - EXCLUDES hidden <input>, hidden <button>, and hidden <textarea> elements
* - EXCLUDES disabled inputs
* - EXCLUDES read-only inputs
*/
var inputs = currentForm.find(':input:enabled:not([readonly], input:hidden, button:hidden, textarea:hidden)')
.not(function () { // do not include inputs with hidden parents
return $(this).parent().is(':hidden');
});
var elFocus = null;
$.each(inputs, function (index) {
var elInput = $(this);
if (elInput.attr('id') == elSelect.attr('id')) {
if ( shiftPressed) { // Shift+Tab
elFocus = inputs.eq(index - 1);
} else {
elFocus = inputs.eq(index + 1);
}
return false;
}
});
if (elFocus !== null) {
// automatically move focus to the next field on the form
var isSelect2 = elFocus.siblings('.select2').length > 0;
if (isSelect2) {
elFocus.select2('open');
} else {
elFocus.focus();
}
}
}
});
/**
* Capture event where the user entered a Select2 control using the keyboard.
* http://stackoverflow.com/questions/20989458
* http://stackoverflow.com/questions/1318076
*/
docBody.on('focus', '.select2', function(e) {
var elSelect = $(this).siblings('select');
if (elSelect.is('[disabled]')==false && elSelect.is('[data-s2open]')==false
&& $(this).has('.select2-selection--single').length>0) {
elSelect.attr('data-s2open', 1);
elSelect.select2('open');
}
});
});