Question

在从html选择处理“变革”活动时,我想获得最后选定的价值/指数。

页: 1

$( #mySelect ).live( change , function(event){
       var idx = $(this).prop( selectedIndex );
});

补贴在改变事件发生后保持价值。我需要事先确定的事件触发点的价值。

Answer 1

如果你们有多种选择的话,就象这样:

var select = $( #mySelect );
select 
    .data("lastIndex", select[0].selectedIndex)
    .live( change , function(event){
        var idx = this.selectedIndex;
        var prevIdx = $(this).data("lastIndex");

        // Alert prev and new index
        alert(prevIds + " - " + idx);

        // Alert prev value and new value
        alert($(this).find("option").eq(prevIdx) + " - " + $(this).find("option").eq(idx));

        // Set new index as old index
        $(this).data("lastIndex", idx);
    });

Answer 2

我将储存不同变量的以往价值,并以人工更新。

// what is the value when <select> was just loaded?
var previous_value = $( #mySelect ).prop( selectedIndex );

$( #mySelect ).live( change , function(event){
       var idx = $(this).prop( selectedIndex );
       // at this point previous_value has the previous value and idx - current
       // ... do something here ...
       // updating previous_value for the next time
       previous_value = idx;
});

Answer 3

你们能够利用你处理事件职能之外的可弥补的范围,追踪价值,例如:

var mySelect = $( #mySelect ),
    previousValue = mySelect.val();

mySelect.live( change , function() {

    alert( mySelect.val() ); // alerts current value
    alert( previousValue ); // alerts previous value

    previousValue = mySelect.val(); // save so it can be referenced next time

});

Answer 4

你可以尝试像这样的东西。

var lastSeelctedlist = "";
$( #mySelect ).live( change , function(event){
       lastSeelctedlist  = $(this).val();
// you rest of code
});

Answer 5

如果是你正确的话,那是纯javascript的解决办法。

function getLastSelected(e)
   {
    var s = e;
    var optionsSelected = [];
    for(var i =0;i<s.options.length;i++)
    {
     if(s.options[i].selected == true)
      {
        optionsSelected[optionsSelected.length] = {Value :  s.options[i].value,Text:s.options[i].text,Index : i};
      }
    }

    var lastSelected =((optionsSelected.length >0)?(optionsSelected[optionsSelected.length - 1]):(null)) ;
    return lastSelected; // or do what you have to do here 
//put it in custom attribute or what ever 
   }

this function parameter is select tag id and return object is contains 3 properties Value,Text,Index

呼吁举行变革活动

onchange = "getLastSelected(this)"

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