Add and Remove table row (javascript).

Hi everyone,
Now I will share a simple script how to Add and Remove table row by javascript.
exactly it was my problem before, it made me very confused because sometime when it work, it removed wrong row, so oh god . . .
But now I have fixed it.

I have a table with some task,

When we click delete button, it will delete the right row and if we click add button it will automatically add new row on the last of table.
Look for the script below :

#javascript

<script type="text/javascript">
    function remove(id){
        // initial variable
        var table = document.getElementById('schedule'); // get table id
        var rows = table.getElementsByTagName('tr'); // get all table rows
        var target = id; // row will remove
        var j = 1;
        
        for(i=0;i<rows.length;i++,j++){
            if(rows[i].id==target){
                table.deleteRow(i); 
                i--;
            }else{
                j--;
            }
        }
    }
    
    function add(){
        var table = document.getElementById('schedule'); // get table id
        var lastRow = table.getElementsByTagName('tr').length; // get last row
        var newId = lastRow+1; // make new id
        
        var row = document.getElementById('schedule').insertRow(lastRow); // create row
        row.setAttribute('id','task'+newId); // insert row id
        
        var cell0 = row.insertCell(0);// create cell 1
        var cell1 = row.insertCell(1);// create cell 2
        cell0.innerHTML = 'Task '+newId+' - Default'; // insert data cell 1
        cell1.innerHTML = '<a style="cursor:pointer;" onClick="remove(\'task'+newId+'\');" >X</a>';// insert data cell 2
    }
</script>

#HTML script

<table cellpadding="0" cellspacing="0" width="300" border="1" id="schedule">
<?php
 for($i=1; $i<5; $i++){
?>
  <tr id="task<?php echo $i; ?>">
            <td>Task <?php echo $i; ?> - Default</td>
            <td><a style="cursor:pointer;" onClick="remove('task<?php echo $i; ?>');" >X</a></td>
        </tr>
<?php
 }
?>
</table>
<input type="button" onClick="add();" value="add" /> 

Hope it useful for all, if you have question, just write your comment below.

Good luck :)