使用 jQuery 限制 textarea 中的行数和显示行数 [英] Limit number of lines in textarea and Display line count using jQuery

问题描述

我想使用 jQuery:

Using jQuery I would like to:

• 将用户可以在 textarea 中输入的行数限制为一组数
• 显示行计数器，在输入行时更新行数
• 回车键或 算作一行

• Limit the number of lines a user can enter in a textarea to a set number
• Have a line counter appear that updates number of lines as lines are entered
• Return key or would count as line

$(document).ready(function(){
  $('#countMe').keydown(function(event) {
    // If number of lines is > X (specified by me) return false
    // Count number of lines/update as user enters them turn red if over limit.

  });   
});


<form class="lineCount">
  <textarea id="countMe" cols="30" rows="5"></textarea><br>
  <input type="submit" value="Test Me">
</form>

<div class="theCount">Lines used = X (updates as lines entered)<div>

在这个例子中，假设允许的行数限制为 10.

For this example lets say limit the number of lines allowed to 10.

推荐答案

html:

<textarea id="countMe" cols="30" rows="5"></textarea>
<div class="theCount">Lines used: <span id="linesUsed">0</span><div>

js:

$(document).ready(function(){

    var lines = 10;
    var linesUsed = $('#linesUsed');

    $('#countMe').keydown(function(e) {

        newLines = $(this).val().split("
").length;
        linesUsed.text(newLines);

        if(e.keyCode == 13 && newLines >= lines) {
            linesUsed.css('color', 'red');
            return false;
        }
        else {
            linesUsed.css('color', '');
        }
    });
});

小提琴:http://jsfiddle.net/XNCkH/17/

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