Javascript - 仅从 textarea 中选择前 5 个非空行

Question

在一个简单的 HTML 脚本中，我有两个元素:textarea 和一个无效的 Javascript 脚本(如下)。我的目标是只从文本区域中选择最多前 5 个非空行(每行由\n 分隔)。这段代码:

var textarea = document.getElementbyId('data').value;

从文本区域中选择所有 (10) 行，但我只想选择最多 5 行并忽略其余行。我把我不成功的尝试放在这里 - http://jsfiddle.net/1xst7e22/

---

文本区域

<textarea id="data" style="width:100%;height:300px">
January
February

March
April
May
June
July
August
September
October
November
December
</textarea>

JAVASCRIPT(这是我悲惨的尝试，没有工作..):假设 x = 5:

function getLines (x)
{
var textarea = document.getElementbyId('data');
var firstX = (textarea.value ? textarea.value + "\n" : "");

      if (firstX.length > x) firstX = firstX.slice(x);

      textarea.value = firstX.join("\n");
}

--

所以当脚本运行时，textarea = document.getElementbyId('data').value;应该只保留这些行:

January
February
March
April
May

Answer 1

var data = document.getElementById('data');
var dataArray = data.value.split("\n");
dataArray = dataArray.slice(0,5);
data.value = dataArray.join("\n");

<textarea id="data" style="width:100%;height:300px">
January
February
March
April
May
June
July
August
September
October
November
December
</textarea>