title: How to set different column in table to be different width in css?
body: <p>There is a table which contain 3 columns.
  Now i want to set the first column 100px width,the second column 200px and the last column 300px.<br>
  It is a awkward to set all the td with a id which inicate which columns it is .<br>
  Is there a more wise way to do ?</p>