Failed to change gridview columns text with Jquery

[heroo0]

\[code\]$('#<%= gv.ClientID %> :submit[value=http://stackoverflow.com/questions/12634600/Apply]').click(function (event) { event.preventDefault(); //***** THIS LINE*******// var row = $(this).parents("tr:first"); var oitemtemplate= row.children("td:eq(4)"); var amt= row.children("td:eq(3)"); var noChild = oitemtemplate.find('select[id$=ddlSubscribe]').val(); childSelectedItems = new Array(); childSelectedItems = noChild.split('|'); amt.text(childSelectedItems[1]);});\[/code\]My gridview contain button for each row , and user will click this button to submit the changes value of dropdownlist in same row back to server, but before submitting to server i like to change the "amt" column's text to something else.i'm not sure why "amt" column only change if i put this line event.preventDefault(); // THIS LINE**//. If remove this it's NOT working.Please help, Thanks.