It is necessary to count empty lines in the table between text lines.
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  • you need to select all the rows, select empty lines from the resulting collection, get the length of the selected collection - Grundy

3 answers 3

var table = document.querySelector('table'), tdIndex = 1; var n = 0; // Счётчик пустых // Делаем цикл по всем tr в таблице for(var i = 0, tr = table.querySelectorAll('tr'); i < tr.length; i++){ // Проверяем, пустой ли td if(tr[i].querySelectorAll('td')[tdIndex].innerHTML == ''){ n++; // Прибалвяем 1 к счётчику }; }; console.log(n); // Выводим количество пустых 
 <table border="1"> <tbody> <tr><td>Строка</td><td></td></tr> <tr><td>Строка</td><td>0</td></tr> <tr><td>Строка</td><td>0</td></tr> <tr><td>Строка</td><td></td></tr> <tr><td>Строка</td><td>0</td></tr> <tr><td>Строка</td><td></td></tr> <tr><td>Строка</td><td>0</td></tr> <tr><td>Строка</td><td></td></tr> </tbody> </table>

  • doing a search by a selector in a loop condition ( tr = table.querySelectorAll('tr') ) is not the best idea since t. performance. it is also better to use the built-in table.rows selectors instead of table.querySelectorAll('tr') , table.cells[tdIndex] instead of table.querySelectorAll('td')[tdIndex] - Sasha Omelchenko

 // Проверяется ячейка с индексом 1 console.info(Array.from(document.querySelectorAll('table tr')).filter(tr => tr.cells[1].innerHTML.trim() === '').length); 
 <table border="1"> <tbody> <tr><td>Строка</td><td></td></tr> <tr><td>Строка</td><td>0</td></tr> <tr><td>Строка</td><td>0</td></tr> <tr><td>Строка</td><td></td></tr> <tr><td>Строка</td><td>0</td></tr> <tr><td>Строка</td><td></td></tr> <tr><td>Строка</td><td>0</td></tr> <tr><td>Строка</td><td></td></tr> </tbody> </table>

  • A beautiful answer, and much better than the first) Good decision! - Vasily Barbashev
  • @ Vasily Barbashev, I turned red as my ava :) Thank you. - user207618
  • @Other Very cool. bravo for this answer - L. Vadim
  • @ L.Vadim, s-media-cache-ak0.pinimg.com/236x/15/3e/b9/… - user207618
  • It's a pity that Explorer doesn't support Array.from - L. Vadim

Watching how empty. If it is assumed that they have nothing at all in the markup (including a number of spaces), then you can:

 console.log(document.querySelectorAll("td:nth-child(2):empty").length) 
 table, tr, td { border-collapse: collapse; border: 1px solid; } td:empty { background: silver; } 
 <table> <tr><td>Строка</td><td></td></tr> <tr><td>Строка</td><td>0</td></tr> <tr><td>Строка</td><td>0</td></tr> <tr><td>Строка</td><td></td></tr> <tr><td>Строка</td><td>0</td></tr> <tr><td>Строка</td><td></td></tr> <tr><td>Строка</td><td>0</td></tr> <tr><td>Строка</td><td></td></tr> </table>

  • It looks pretty dangerous, any gap or carry breaks the count. But it's still cool :) - user207618
  • @Other, yes, it will break. This is written in the answer. - Qwertiy ♦
  • Thanks, Cap. Another bad thing is that the scalability is bad. - user207618
  • @Other scalability? - Qwertiy ♦
  • Well, yes, suddenly you need to change the rules and assume that they are empty and where will be 0 ? - user207618