how to add data to array and check whethere it exist in arr

Question

 

in my gridview  i have text box  for emailid in that  i want make validation  for same emailid  does not  submit to db on button click

 

for that   i wrote java script

function OnSubmit() {

debugger;

var Table_Value = new Array();

var j = 1;

var strValue;

var Grdemilid = document.getElementById('ctl00_ContentPlaceHolder1_Grdemilid');

var len = Grdemilid.rows.length;

for (i = 0; i < Grdemilid.rows.length; i++) {

var txtUnitsArray = $("input[id*=txtemailid]");

var txtemailid = new Array(500)

txtemailid= txtUnitsArray[i].value;

}

return false;

}

 in that i will get last email id in loop in array .but i want  all email id  to be added in arrlist can u help me thank you