javascript - 如何在 Javascript 中向文本区域添加多个值？

Question

我是 Javascript 新手，正在解决一个问题，它是关于制作一个网站，允许用户输入对项目的出价以及出价 ID。当他们输入两者时，他们按下提交按钮，出价/出价 ID(以及日期和时间)将显示在文本区域中。

它应该允许提交和显示多个出价，但目前我只能显示一个出价。任何关于如何获得多个出价显示的帮助将不胜感激。谢谢

var bids = new Array();
var bidders = new Array();
var bidTime = new Array();

function writeBid() {
     var historyText = " ";
     for (var i = 0; i < bids.length; i++) { 
     historyText = bidTime[i] + " " + bids[i] + " " + bidders[i] + "\n";
     document.bidForm.bidList.value = historyText;
     document.bidForm.highBid.value = bids[i];
     document.bidForm.bidId.value = " ";
     document.bidForm.bidAmount.value = " ";
     }
}
function addBid() {
     bidders.unshift(document.bidForm.bidId.value);
     bids.unshift(document.bidForm.bidAmount.value);
     var now = new Date();
     var hours = now.getHours();
     var minutes = now.getMinutes();
     var seconds = now.getSeconds();
     var timeText = hours + ":" + minutes + ":" + seconds;
     bidTime.unshift(timeText);
     writeBid();
 }
 function removeBid() {
     bids.shift();
     bidders.shift();
     bidTime.shift();
     writeBid();
 }

Answer 1

正如 @nnnnnn 所说，将 += 与文本变量一起使用效果非常好:

JavaScript

var bids = [10, 20, 30];
var bidders = ['tim', 'sam', 'john'];
var bidTime = ['10/2/2013','12/5/213','14/1/2023'];

function writeBid() {
  var historyText = " ";
  for (var i = 0; i < bids.length; i++) { 
    historyText += bidTime[i] + " " + bids[i] + " " + bidders[i] + "\n";
    document.bidForm.highBid.value = bids[i];
    document.bidForm.bidId.value = " ";
    document.bidForm.bidAmount.value = " ";
  }
  document.bidForm.bidList.value = historyText;
}

HTML

<form name="bidForm" id="bidForm">
  <input type="text" name="bidId" id="bidId"/>
  <input type="text" name="bidAmount" id="bidAmount"/>
  <input type="text" name="highBid" id="highBid"/>
  <textarea name="bidList" id="bidList"></textarea>
</form>