Checking a checkbox by Id

I am using the following piece of code to check some checkboxes based on their Id and a value stored in a array. So if the array has a value, the corresponding checkbox should become checked.

for($k=0;$k<count($array_ids);$k++){
     echo'<script type="text/javascript">

    var cb = document.getElementsById("id_'.$array_ids[$k].'");
    cb.checked = true;

</script>';
}

And this is the code for the checkboxes:

<input type="checkbox" id="id_'.$array_ids[$k].'" name="'.$array_ids[$k].'" value="checked" class= "My_class" onchange="add_on_textBox(this,\''.$array_ids[$k].'\',\'My_class\')">

And this is the var_dump result for the $array_ids:

array(2) {
  [0]=>
  string(5) "Name1"
  [1]=>
  string(5) "Name2"
}

The code doesn't work. I am pretty sure I am missing something.