How to get All Gridview Value Using JavaScript

I am write this code now but they work not properly  

i try to number of product display in grid and enter quantity of product and save all product data in database but they not work proper..

 

var product_name =$('#prd').val();

var fran_rate =$('#rate').val() ;

var txtQty = $('#qty').val();

var txtPatRate =$('#pat').val();

var product = Array();

$("#gvData").find('tr:has(td)').each(function ()

{

    product.product_code = $(this).find("td:nth-child(1)").html();

    product.product_name = $(this).find("td:nth-child(2)").html();

    product.product_txtQty = $(this).find("td:nth-child(3)").html();

    product.product_txtPatRate = $(this).find("td:nth-child(4)").html();

} 

alert(product_code[i] + product_name[i] + fran_rate[i] + txtQty[i] + txtPatRate[i]);

 

please reply as soon as... 

Thanks..