javascript - Javascript 如何在 Textarea 表单字段中获取准确的字符数

Question

我一直在谷歌和线程中搜索如何解决这个问题，但没有找到我需要的东西。我正在使用 JS 对表单中的 textarea 字段进行一些字符倒计时。在我尝试使用提交的数据之前，我的做法非常标准并且有效。

我的代码：

$(document).ready(function(){

  $('#available_days_times').keyup( function(){
    showLength( $('#available_days_times'), $('#available_days_times_label'), 1000 );
  });
  ...
});


function showLength(field_id, label_id, maxLength){
    var currentLength = field_id.val().length;
    var charactersLeft = maxLength - currentLength;

    label_id.addClass("red");
    if( currentLength >= maxLength ) {
        charactersLeft = 0;
        field_id.val( field_id.val().substring(0, maxLength-1) )
    }
    label_id.text("Characters allowed: " + maxLength + " You have " + charactersLeft + " characters left");
}

这工作正常，直到我复制粘贴超过 1000 个字符的文本（如下）。代码将其截断为 1000 个字符，但在将表单数据提交到数据库表时出现大小错误。maxLength 等于该字段的 db table.column 的大小。

这是我用于测试的文本示例：

sunday = n/a
monday = 8:00am to 4:00pm
wednesday = 8:00am to 5:00pm
friday = 12:00pm to 5:00pm
saturday = 5:00pm to 9:00pm
sunday = n/a
monday = 8:00am to 4:00pm
wednesday = 8:00am to 5:00pm
friday = 12:00pm to 5:00pm
saturday = 5:00pm to 9:00pm
sunday = n/a
monday = 8:00am to 4:00pm
wednesday = 8:00am to 5:00pm
friday = 12:00pm to 5:00pm
saturday = 5:00pm to 9:00pm
sunday = n/a
monday = 8:00am to 4:00pm
wednesday = 8:00am to 5:00pm
friday = 12:00pm to 5:00pm
saturday = 5:00pm to 9:00pm
sunday = n/a
monday = 8:00am to 4:00pm
wednesday = 8:00am to 5:00pm
friday = 12:00pm to 5:00pm
saturday = 5:00pm to 9:00pm
sunday = n/a
monday = 8:00am to 4:00pm
wednesday = 8:00am to 5:00pm
friday = 12:00pm to 5:00pm
saturday = 5:00pm to 9:00pm
sunday = n/a
monday = 8:00am to 4:00pm
wednesday = 8:00am to 5:00pm
friday = 12:00pm to 5:00pm
saturday = 5:00pm to 9:00pm
sunday = n/a
monday = 8:00am to 4:00pm
wednesday = 8:00am to 5:00pm
friday = 12:00pm to 5:00pm
saturday = 5:00pm to 9:00pm
sunday = n/a
mond

如果我将其复制粘贴到表单的 textarea 中，javascript 将其视为 999 个字符，但我的数据库将其视为 1038 并抛出一个合适的字符。

由于没有真正奇怪的字符，我认为 javascript 没有将返回数计为两个字符。大约有 40 行，大约匹配 999 和 1038 之间的差异。

有没有办法，使用 JavaScript 来获得与 db 看到的计数相匹配的字符的准确计数？

谢谢你的帮助。

标签： javascript