Javascript 我的if和else语句是如何执行的？

这段代码运行得很好-但我的if和else语句都在执行，这是我以前从未见过的，也无法理解：

function submit(total_lines) {

  total_lines   = total_lines;
  completed_lines         = 0;   

  /* create one line at a time... */
  for (i=0;i<total_lines;i++) {    

    color      = $('#color_' + i).val();
    qty        = $('#qty_' + i).val();

    console.log("starting line " + completed_lines);        

    if ( color && qty ) {
      $.ajax({
        type: 'POST',                                                       
        url: '/submit_line.php',              
        data: { color:color, qty:qty },
        success:function(data){                                                                                                                                      
          console.log("Line " + completed_lines + " was successfull");              
          completed_lines++;
        }                                                
      }); //close ajax         
    } else {
       console.log("Line " + completed_lines + " was not successfull. color = " + color + " and qty = " + qty);          
       toastr.error("Color and quantity are both required fields.");
    }  
  }

  setTimeout(function(){
    toastr.success("All done! ..."); 
    $('#add_something_footer').html('<div class="footer_buttons_holder"><div onclick="close_swal()" class="footer_cancel_button">CLOSE</div></div>');     
  }, 5000);

}

---

事实上，在我的控制台中，所有行都首先通过

else

语句，因为变量未定义，然后再次通过常规

if

语句，因为它们已定义，这让我感到困惑。如果我直接在

ajax

行上方定义变量，那么变量

怎么可能是未定义的呢？
你确定
color
和
qty
在每次迭代中都有真实值吗？你能创建一个plunkr或fiddle吗？你能在你的ajax成功中添加一个console.log（），查看相对于错误调用了多少次。我不认为if和else是同时调用的。@BrianPowell很可能不是在同一时间触发的，而是在
for
循环的不同迭代中触发的。使用
console.log（）
在每次迭代中观察这些变量的状态成功时，您只会增加
completed\u行
，这意味着如果一行中有5行失败，它们都会返回相同的结果，因为
“行”+completed\u行+“未成功。”
您没有得到失败的行，您只是得到了
上一次成功的迭代+1
。
Object {type: "info", iconClass: "toast-info", message: "Submitting quotes...", optionsOverride: undefined, title: undefined}
5VM7093:699 starting line 0
VM7093:712 Line 0 was not successfull. color = undefined and quantity = undefined
toastr_qt.js:227 Object {type: "error", iconClass: "toast-error", message: "Color and quantity are both required fields", optionsOverride: undefined, title: undefined}
VM7093:699 starting line 0
VM7093:712 Line 0 was not successfull. color = undefined and quantity = undefined
toastr_qt.js:227 Object {type: "error", iconClass: "toast-error", message: "Color and quantity are both required fields", optionsOverride: undefined, title: undefined}
VM7093:699 starting line 0
VM7093:712 Line 0 was not successfull. color = undefined and quantity = undefined
toastr_qt.js:227 Object {type: "error", iconClass: "toast-error", message: "Color and quantity are both required fields", optionsOverride: undefined, title: undefined}
VM7093:699 starting line 0
VM7093:712 Line 0 was not successfull. color = undefined and quantity = undefined
toastr_qt.js:227 Object {type: "error", iconClass: "toast-error", message: "Color and quantity are both required fields.", optionsOverride: undefined, title: undefined}
VM7093:699 starting line 0
VM7093:712 Line 0 was not successfull. color = undefined and quantity = undefined
toastr_qt.js:227 Object {type: "error", iconClass: "toast-error", message: "Color and quantity are both required fields.", optionsOverride: undefined, title: undefined}
VM7093:708 Line 1 was successfull
VM7093:708 Line 2 was successfull
VM7093:708 Line 3 was successfull
VM7093:708 Line 4 was successfull
toastr_qt.js:227 Object {type: "success", iconClass: "toast-success", message: "All done!", optionsOverride: undefined, title: undefined}