Question

var stocks = [
['Apple',100,8998,723,7212],
['Microsoft',928,1992,821,2381]
];
var select = document.getElementById("selectStock");
for(var i = 0; i < stocks.length; i++) {
    var opt = stocks[i][0];
    var el = document.createElement("option");
    el.textContent = opt;
    el.value = opt;
    select.appendChild(el);
}

<select id="selectStock">
    <option>Choose a stock</option>
</select>

我有多个Javascript数据数组（从Excel中提取），并且具有基本上基于数组行进行计算的不同函数。例如：

var stocks = [['Apple',100,8998,723,7212]['Microsoft,928,1992,821,2381]]

我需要做的是制作一个下拉菜单，允许用户选择一个选项（Microsoft或Apple），然后根据此选择，将此值拉入公式进行计算

document.write(Math.round(stocks[i][1] * 100)/100 + " dollars per share");

其中i是基于关闭下拉菜单选项的变量。这有意义吗？我不确定如何处理这个，这是个人项目。谢谢你的帮助！

Answer 1

https://jsfiddle.net/b22y3v85/

var select = document.getElementById("selectStock");
select.onchange = (e) => {
   let index = stocks.indexOf(stocks.find(a => a.indexOf(e.target.value) > -1));
   document.write(Math.round(stocks[index][1] * 100)/100 + " dollars per share");
};

Answer 2

这是一个工作示例，尽管您可能希望执行除document.write之外的其他操作。

var stocks = [
  ['Apple',100,8998,723,7212],
  ['Microsoft',928,1992,821,2381]
];

var select = document.getElementById("selectStock");

for(var i = 0; i < stocks.length; i++) {
    var opt = stocks[i][0];
    var el = document.createElement("option");
    el.textContent = opt;
    el.value = opt;
    select.appendChild(el);
}

function getPrice(stock) {
  var price = false;
  for (var a = 0; a < stocks.length; a++) {
    if (stocks[a][0] == stock) {
      price = stocks[a][1];
      break;
    }
  }
  if (!price) { alert("Incorrect choice."); return; }
  document.getElementById("result").innerText = stock + " is currently " + (Math.round(price * 100)/100 + " dollars per share");
}

<select id="selectStock" onchange="getPrice(this.value);">
    <option>Choose a stock</option>
</select>

<br><br>
<div id="result"></div>

编辑：在页面上显示div的结果，而不是使用document.write()覆盖页面。

Answer 3

<...>   
private int playerHealth;
public bool isDead;
<...>   
void Start ()
{
    playerHealth = 3;
    isDead = false;
}
<...>   
public void SubLive()
{
    playerHealth--;
    UpdateLives ();
    if (playerHealth <= 0) 
    {
        isDead = true;
    }
}

void UpdateLives ()
{
    livesText.text = "Lives: " + playerHealth;
}

根据下拉菜单中的选项进行公式/计算？

3 个答案: