Here I have used Simple Javascript instead of Jquery
<input class="product_text" onClick="AddNewRow()" type="button" id="addRow" name="addRow" value="Add">
function AddNewRow()
{
var table = document.getElementById("product_table");
var row = table.insertRow(table.rows.length);
var cell1 = row.insertCell(0);
var cell2 = row.insertCell(1);
var cell3 = row.insertCell(2);
cell1.innerHTML = "<input type='text' class='product_text' placeholder ='Type product Name' />"
cell2.innerHTML = "<input type='text' class='product_text' placeholder ='Quantity' />"
cell3.innerHTML = "<input class='product_text' type='button' onClick='AddNewRow()' name='addRow' value='Add'>"
}