着色负数/正数(jQuery)

你走了:

$(document).ready( function() {

  // the following will select all 'td' elements with class "of_number_to_be_evaluated"
  // if the TD element has a '-', it will assign a 'red' class, and do the same for green.

  $("td.of_number_to_be_evaluated:contains('-')").addClass('red');
  $("td.of_number_to_be_evaluated:contains('+')").addClass('green');
}

然后使用CSS来设置输入元素的样式:

td.red {
  color: red;
}

td.green {
  color: green;
}