<!DOCTYPE html> <html> <head> <script> function doTest() { document.getElementById("t").style.display = "table-row"; } </script> </head> <body onload="doTest()"> <table style="border-collapse: collapse"> <tr style="display: block; border: 5px solid"> <td>LongLongLong</td> </tr> <tr style="display: none; border: 5px solid" id="t"> <td>Short</td> </tr> </table> </body> </html>