Check All and UnCheck All Functionality


function_ functionCheckUnCheck()
{
var flagCheckUnCheck;
var buttonValue;
if(document.getElementById("btnCheckUnCheck").value == "Check All")
{
flagCheckUnCheck = true;
buttonValue = "UnCheck All";
}
else if(document.getElementById("btnCheckUnCheck").value == "UnCheck All")
{
flagCheckUnCheck = false;
buttonValue = "Check All";
}
var theGridView = document.getElementById("grdvShortTermFTRs");
for ( var rowCount = 1; rowCount < checked =" flagCheckUnCheck;" value =" buttonValue;">

Button:

input_ type="button" id="btnCheckUnCheck" value="Check All" onclick="functionCheckUnCheck()"