To open a new tab you can use the following code.
<input type="button" class="bgbutton" value="Add to Shopping Cart" id="addtocart" name="addtocart" onkeypress="window.event.cancelBubble=true;" onclick="window.open('NewPage.aspx', 'NewPage');" >
To move between pages
<input type="button" class="bgbutton" value="Add to Shopping Cart" id="addtocart" name="addtocart" onkeypress="window.event.cancelBubble=true;" onclick="location.href = 'NewPage.aspx';" >
For more details you may want to refer to the following questions:
In JQuery you can use the following
<script>
$(document).ready(function () {
$(".bgbutton").click(function () {
window.location.href = "NewPage.aspx";
});
});
</script>
You can carry the variables to the other page through the URL like below.
<script>
$(document).ready(function () {
var name = "coder";
$(".bgbutton").click(function () {
window.location = 'NewPage.aspx?username=' + name;
});
});
</script>
To get the passed values to open up in new tab use the following
<script>
$(document).ready(function () {
var name = "coder";
$(".bgbutton").click(function () {
window.open('NewPage.aspx?username=' + name,"")
});
});
</script>
In order to understand how to retrieve a value from a URL, you might want to refer to the following question: Get url parameter jquery Or How to Get Query String Values In js