Hi,
you can use my way of passing multiple values to external js file
<asp:HiddenField ID="HiddenField1" Value="2" runat="server" />
<asp:HiddenField ID="HiddenField2" Value="2" runat="server" />
<asp:Button ID="Button3" runat="server" Text="Button" OnClientClick = "passvalue()" />
<script src="htmldiff.js"></script>
<script type="text/javascript" >
function passvalue()
{
var original = document.getElementById("<%=HiddenField1.ClientID%>");
var changed = document.getElementById("<%=HiddenField2.ClientID%>");
let output = diff(original.value, changed.value);
alert(output);
}
</script>
or you can use the more standard way of making global variable discussed in that
Link1
Link2
I Hope this will help you