required validation is not firing

required validation is not firing

Hi,

i have 2 tab strip i.e general and participants and textboxes on both tabs.
need to put required field validation on both tabs for compulsory fields.
validation is working on first tab while clicking on save button but not of other tab.

if($.trim($('#MainContent_txtboxRequired').val())==' ')
{
alert("Required must be enter..!");
}