This is the example to how to do Ajax call to read message in HTML using JQuery.
<script language="javascript" type="text/javascript">
function ReadMessageCall() {
var pageUrl = '<%=ResolveUrl("~/WebService/Webservice1.asmx")%>'
$.ajax({
type: "POST",
url: pageUrl + "/ReadMessage",
data: "{'mail':'" + $('#<%=txtemail.ClientID%>').val() + "'}",
contentType: "application/json; charset=utf-8",

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