2

我试图通过组合两个变量来将一个新变量设置为与已经声明的变量相同的值，这两个变量一起构成原始变量的名称......这听起来可能令人困惑，所以这里有一个例子：

// JavaScript Document


document.write (finalVar);

$(document).ready(function()
{ 
 var position_1 = $("#box_1").position();
 var left_1 = position_1.left;
 var top_1 = position_1.top;
 var position_2 = $("#box_2").position();
 var left_2 = position_2.left;
 var top_2 = position_2.top;
 var box;
 var boxLength;
 var boxNumber;
 var selected = 0;


 $("#box_1").click
    (function()
        {
            if (selected == 1) // if a box is selected run the following
                {       
                    box = $(".selected").attr("id");
                    boxLength = box.length;
                    boxNumber = box.charAt(boxLength-1); // finds the number of the box
                    alert(+boxNumber);
                if (box == "box_1") // if the selected box is itself     then mimimise the box, remove the selected class from it and set selected to zero
                    {
                        $("#box_1").animate({height:50,opacity:0.8,left:left_1,top:top_1,borderRadius:4,MozborderRadiu  s:4},(60),"swing").animate({width:50},(60),"swing").animate({opacity:0.6},(150),        function()
                        {
                                $(this).removeClass("selected");
                        }); 
                    selected = 0;
                    }
                else
                    {
                        $(".selected").animate({height:50,opacity:0.8,left:left_+boxNumber,top:top_+boxNumber,borderRadius:4,MozborderRadius:4},(60),"swing").animate({width:50},(60),"swing").animate({opacity:0.6},(150),     function()
                        {
                            $(".selected").removeClass("selected");
                            $("#box_1").animate({width:900,left:60,top:0,borderRadius:10,MozborderRadius:10},(60),"swing").animate({height:500},(60),"swing").animate({opacity:1},(150), function()
                                {
                                    $("#box_1").addClass("selected");
                                });
                        }
                );} } // end of function for if a box is selected
            else // if no box is selected run the following
                {
                    $("#box_1").animate({width:900,left:60,top:0,borderRadius:10,MozborderRadius:10},(60),"swing").animate({height:500},(60),"swing").animate({opacity:1},(150), function()
                        {   
                            $("#box_1").addClass("selected");


                        }); 
                    selected = 1;
                }
        });

    $("#box_2").click
    (function()
        {
            if (selected == 1) // if a box is selected run the following
                {       
                    box = $(".selected").attr("id");
                    boxLength = box.length;
                    boxNumber = box.charAt(boxLength-1); // finds the number of the box
                    alert(+boxNumber);
                if (box == "box_2") // if the selected box is itself then mimimise the box, remove the selected class from it and set selected to zero
                    {
                        $("#box_2").animate({height:50,opacity:0.8,left:left_2,top:top_2,borderRadius:4,MozborderRadius:4},(60),"swing").animate({width:50},(60),"swing").animate({opacity:0.6},(150),  function()
                        {
                                $(this).removeClass("selected");
                            selected = 0;   
                        }); 
                    }
                else
                    {
                    $(".selected").animate({height:50,opacity:0.8,left:left_+boxNumber,top:top_+boxNumber,borderRadius:4,MozborderRadius:4},(60),"swing").animate({width:50},(60),"swing").animate({opacity:0.6},(150),     function()
                        {
                            $(".selected").removeClass("selected");
                            $("#box_2").animate({width:900,left:60,top:0,borderRadius:10,MozborderRadius:10},(60),"swing").animate({height:500},(60),"swing").animate({opacity:1},(150), function()
                                {
                                    $("#box_2").addClass("selected");
                                });
                        }
                );} } // end of function for if a box is selected
            else // if no box is selected run the following
                {
                    $("#box_2").animate({width:900,left:60,top:0,borderRadius:10,MozborderRadius:10},(60),"swing").animate({height:500},(60),"swing").animate({opacity:1},(150), function()
                        {   
                            $("#box_2").addClass("selected");
                            selected = 1;
                        }); 
                }
        });

});

然后我希望将 5 写入文档……有什么办法吗？我知道这甚至可能不是开始考虑这样做的正确方法，我只是将它用作我正在尝试做的事情的同义词。

谢谢你的帮助。

4

4 回答 4

5

如果这些是全局变量，您可以这样做：

var position = 4;
var a = "posi";
var b = "tion";

document.write(window[a+b]);

这只是因为所有全局变量实际上都是window对象的属性，并且您可以将窗口对象的属性引用为window.position或window["position"]。由于后者有效，因此您还可以"position"使用字符串操作构造字符串，如上例所示。

我会问你为什么这样做？人们要求这样做的一个常见原因是他们可以访问诸如position1,position2等变量。如果是这种情况，那么更好的答案是使用可以通过索引访问的数组：

var positions = [1,4,67,99];

document.write(positions[3]);

您也可以像这样通过变量访问数组值：

var positions = [1,4,67,99];
var pos = 3;

document.write(positions[pos]);

或者，遍历整个数组：

var positions = [1,4,67,99];

for (var i = 0; i < positions.length; i++) {
    document.write(positions[i]);
}

如果您描述了您要解决的实际问题，我们可以推荐解决问题的最佳方法。您目前所问的问题听起来像是几乎所有问题的错误方法。

于 2012-01-19T17:23:44.807 回答
4

我不知道您为什么要这样做，但是可以使用eval方法。

试试这个

var position = 5;
var pos = "posi";
var tion = "tion";
var finalVar = pos+tion;

document.write (eval(finalVar));

演示

于 2012-01-19T17:25:10.047 回答
1 
var position = 'top';
var pos = "posi";
var tion = "tion";
var finalVar = pos+tion;

alert(window[finalVar]); // better that `eval()`
document.write(window[finalVar]);
于 2012-01-19T17:32:30.697 回答
0

在组合变量时使用它 parseInt(pos)+parseInt(ition) 不要忘记声明字符串变量 pos 和 ition... :)

于 2012-01-19T17:27:32.970 回答