JQuery :: What Is The Difference Between Append() And InsertAfter()

I want to give functinality to add and remove rows dynamically using jQuery.

if i add a row in table using "append()" and try to access newly added row,( with last() or slice() ) then it references the the last row before new rows inserted dynamically.

Instead if i use insertAfter(), i can reference the new rows correctly.what can be the issue?

Works wrongly:

$("#tbl2 > tbody > tr").last().append('<tr"><td>1</td><td>2</td><td>3</td></tr>');
$("#tbl2 > tbody > tr").last().remove();

Works as desired :

$('<tr"><td>1</td><td>2</td><td>3</td></tr>').insertAfter($("#tbl2 > tbody > tr").last());
$("#tbl2 > tbody > tr").last().remove();