how can I have a checkbox as selected in Javascript? : I have some items to be selected,they are checkboxes with their certain titles in a table  .I want to onclick on an item(I mean each "td") then the function do its job but besides I want the checkbox of that selected "td" t be checked .how can I do it with javascript?
note:I am learning javascript so please don't answer with a jquery solution.
the code below is an example of each items
<td id="1" onclick="chb('1')" ><input  type="checkbox" />title</td>