如何将参数传递给setTimeout调用中定义的匿名函数? [英] How to pass parameter to an anonymous function defined in the setTimeout call?

问题描述

这是我的代码:

function addRcd2(timeOut){  
  for(var c=0; c less 5; c++){
    var rcdi = "rcd_"+c+"";
    setTimeout(function(){
      $('.tbl1 tbody').append(rcdi);
    },timeOut*c);
  }
}

此代码的输出是一个表，其中行具有相同的文本rcd_5.

The output of this code is a table which rows have the same text rcd_5.

我的目标是使表行具有不同的记录rcd_1，…，rcd_5.

My goal is to have a table rows have different records rcd_1, …, rcd_5.

有什么想法吗?

推荐答案

典型的循环创建函数问题.您传递给setTimeout的所有闭包都引用了相同 rcdi变量.在循环内定义变量与在循环内定义变量相同:

Typical creating a function in a loop problem. All closures you pass to setTimeout have a reference to the same rcdi variable. Defining the variable inside the loop is the same as defining it outside:

var rcdi;
for(var c=0; c < 5; c++){
    rcdi = "rcd_"+c+"";
    // ...
}

这使您在这里只处理一个变量更加明显.

which makes it a bit more apparent that you only deal with one variable here.

您必须引入一个新的作用域，这在JavaScript中只能通过函数来​​实现:

You have to introduce a new scope, which in JavaScript can only be achieved through functions:

function getCallback(val) {
    return function(){
      $('.tbl1 tbody').append(val);
    };
}

function addRcd2(timeOut){  
  for(var c=0; c < 5; c++){
    setTimeout(getCallback("rcd_"+c),timeOut*c);
  }
}

如您在其他答案中所见，您还可以使用立即功能.使用您认为更具可读性的内容.

As you can see in other answers, you can also use immediate functions. Use what you find more readable.

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