css and table hiding without using up space

Recently i faced an issue with hiding table without the using up the table space. for some time i had played around with visibility but the solution lay some were in the display attribute of css.

here it is
create to classes in css file
.tableshow{display: block; display: table-row-group;}
.tablehide{display: none;}
add to the tr of table style="display: table-row"
set the class using javascript to the tbody which will decide when to hide the table and when to show it.
var tableLength=document.getElementById("my").rows.length;
if (tableLength==2)
document.getElementById("my").getElementsByTagName("tbody")[0].className="tbodyhide";
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