.each() > $(this).find().eq().html() is null

Why don't work?

var str;

$('table tr').each(function() {
    str = $(this).find('td').eq(6).html().trim().substring(10开发者_开发技巧, 20);
    $(this).find('td').eq(6).text(str);
});

Need write in all 6th trim+substring+another_string_action with same value.

Firebug write error: $(this).find("td").eq(6).html() is null

Two things.

First, remember that not all browsers have a native .trim() function. Safer to use jQuery's $.trim().

• http://api.jquery.com/jquery.trim/

Second, remember that .eq() takes a 0 based index, so if you want the sixth <td> column, pass 5. Right now you're asking for the seventh <td>.

var str;

$('table tr').each(function() { 
    var $td = $(this).find('td').eq(5); // Get sixth <td> in the row
    str = $.trim( $td.html() ).substring(10, 20);
    $td.text(str);
});

You should avoid repeating the lookup of the table cell anyway:

$('table tr').each(function() {
  var cell = $(this).find('td').eq(6);
  if (cell.length) {
    cell.text(cell.html().trim().substring(10, 20));
  }
});

It might also be good to check the original string to make sure it's as long as the code expects. Finally, you get the contents with .html() but then you set with .text(). Is that really what you want?