Question

构建一个函数来从一组元素返回元素的索引。但是当我尝试将值传递给另一个变量（myindex）时，我确实得到了未定义。

这里是Javascript源代码

$(document).ready(function(){
             $("[id*='_CG']").addClass("form-control input-sm text-right");
    $("[id*='_Weight']").addClass("form-control input-sm text-right");
    $("[id*='TXFuelWeight']").addClass("form-control input-sm text-right");
    $("[id*='TRPFuelWeight']").addClass("form-control input-sm text-right");

      myindex = GetLSElementIndex("[id*='W_OP_']", "W_OP_CAB1Items");
alert (myindex);

            });
 // Get the index element in a group of element
 function GetLSElementIndex(ElementGroup, Element) {
    $(ElementGroup).each(function (index) {
        var someText = $(this).attr('id');
        if (someText == Element) {
            alert(someText);
            alert(index);
            //GetLSElementIndex = index;
            //alert(GetLSElementIndex);
            return ;
            //return index;

        }


    });

}

Example

Answer 1

你需要像这样使用：

var indx;
if (someText == Element) {
    alert(someText);
    alert($('#'+Element).index());//Don't do just alert(index)
    indx = $('#'+Element).index();//I need to find index of ? #W_OP_CAB1Items
     return indx;
  }

Answer 2

function GetLSElementIndex(ElementGroup, Element) {
    var value = -1; //If no element is found, index is assumed to be -1
    $(ElementGroup).each(function (index) {
        var someText = $(this).attr('id');
        if (someText == Element) {
            alert(someText);
            value = index;
            alert(value);
            return false;//To break out of each() once the index is found.
        }
    });
    return value; //Return the value (from the called fn) once the processing is done

}

Answer 3

通过为该方法定义一个全局变量并将GetLSElementIndex循环的索引指定给它并返回它然后将return语句从{{1}中移出来重写这样的each方法}循环。

DEMO：FIDDLE

each

注意：此方法仅返回// Get the index element in a group of element function GetLSElementIndex(ElementGroup, Element) { var setIndex; $(ElementGroup).each(function (index) { var someText = $(this).attr('id'); setIndex = index; if (someText == Element) { alert(someText); alert(index); } }); return setIndex; }循环的最后一项的索引。

Answer 4

你必须打破“Jquery each”并返回索引。混淆点是“Jquery each”打破“return false”声明。您必须将索引值存储在某个局部变量中（var toReturn ..在下面的函数中）。这是修改后的GetLSElementIndex函数

 // Get the index element in a group of element
 function GetLSElementIndex(ElementGroup, Element) {
   var toReturn; 
    $(ElementGroup).each(function (index) {
        var someText = $(this).attr('id');

       if (someText == Element) {
            //alert(someText);
           // alert(index);
            toReturn= index;
            //GetLSElementIndex = index;
            //alert(GetLSElementIndex);
            return  false ;
            //return index;

        }

    });
     return toReturn;

}

有关详细信息，请关注other question of Stack Overflow

Answer 5

更新函数以将所需元素的索引存储在变量中，然后返回变量。

function GetLSElementIndex(ElementGroup, Element) {
   var elementIndex;/* store the index of #element here */  
   $(ElementGroup).each(function (index) {
       var someText = $(this).attr('id');
       if (someText == Element) {
           elementIndex = index;
       }
   });
   return elementIndex; /* will return index of #element if found otherwise will return undefined */
}

已删除所有警报，因为我认为这些警报是出于调试目的。

函数未返回值 - 未定义

5 个答案: