Jquery 如何从multiselect中获取最后选定的选项？

我正在寻找一种方法，使用jQuery以多选形式获取最后一个用户选择的选项

我不是在查找列表上的最后一项，而是在查找用户单击的最后一项。

类似于这样的内容

var lastSelected = null;
$('.multiSelectOptions').click(function(){
    lastSelected = this.value;
});

---

当用户按住Ctrl键并单击并选择多个项目时，使用上述答案中的

this.value

将失败——它返回列表中第一个选择的值，即使这不是最后一次单击的值。试试这个：

var previouslySelected = [];
$("#myMultiselect").change (function() {
    // Get newly selected elements
    var currentlySelected = $(this).val();
    var newSelections = currentlySelected.filter(function (element) {
        return previouslySelected.indexOf(element) == -1;
    });
    previouslySelected = currentlySelected;

    if (newSelections.length) {
        // If there are multiple new selections, we'll take the last in the list
        var lastSelected = newSelections.reverse()[0];
    }
});

---

基本上，您需要维护一个堆栈，以跟踪最后选定的项目。我编写此函数是为了更新堆栈

var determineLastSelectedReportNumber = function (selectedReportNumbers, oldSelectedReportNumbers) {
    var newlyAddedReportNumbers = 
    selectedReportNumbers.filter(function (n) {
        return oldSelectedReportNumbers.indexOf(n) == -1;
    });

    var removedReportNumbers = 
    oldSelectedReportNumbers.filter(function (n) {
        return selectedNumberArray.indexOf(n) == -1;
    });

    //Remove the removed reportNumbers from the stack.
    if (removedReportNumbers.length > 0) {                        
        removedReportNumbers.forEach(function (removedReportNumber) {
            for (var i = 0; i < selectedNumbersStack.length; i++) {
                if (selectedNumbersStack[i].toString() === removedReportNumber.toString()) {
                    selectedNumbersStack.splice(i, 1);
                    break;
                }
            }
        });
    }

    //Add the added reportnumbers to the stack. Push();
    if (newlyAddedReportNumbers.length > 0) {
        selectedNumbersStack.push(newlyAddedReportNumbers);
    }

    //Set the last selected from top of the stack. Peek();
    var lastSelectedReportNumber = "";
    if(selectedNumbersStack.length > 0){
        lastSelectedReportNumber = selectedNumbersStack[selectedNumbersStack.length -1];
    }

    return lastSelectedReportNumber;
}

我不妨向您展示我的完整代码：

var selectedNumberArray = jQuery.makeArray($('#SelectedReportNumbers').val());
//Initial selectedNumbersStack.
var selectedNumbersStack = selectedNumberArray;

var counterInitialValue = 3;
var counter = counterInitialValue;
var counterInterval = -1;

function delayRetrieveReportInfo() {
    counter--;
    if (counter === 0) {
        retrieveReportInfo($("#TheLastSelectedReportNumber").val());
        clearInterval(counterInterval);
    }
}

function resetDelayRetrieveReportInfo() {
    clearInterval(counterInterval); //The previous interval is cancelled.
    counter = counterInitialValue;
    counterInterval = setInterval(function () { delayRetrieveReportInfo() }, 1000);
}

这是multi-select的连接：

// Hookup function to change events of select lists
$('#SelectedReportNumbers').change(reportNumberChanged);

---

您可以重复使用我的一些代码来创建自己的“lastSelected”实现。

您必须自己跟踪上次选择的项目。1。无需使用

每个
，以及2。当
此.value
更容易时，不要使用
$（this）.val（）
。
// Hookup function to change events of select lists
$('#SelectedReportNumbers').change(reportNumberChanged);