If you are using Microsoft IE 5 or later, you can use the behavior/HTML-Component "WebService" to access a Web service. The "WebService" behavior communicates with Web services over HTTP using Simple Object Access Protocol (SOAP).
To use the "WebService" behavior, you must attach it to an element using the STYLE attribute, as follows:
<DIV ID="GiveItAName"
STYLE="behavior:url(webservice.htc)"></DIV>
A complete example taken from the Microsoft Web site is as follows:
<html>
<head>
<script language="JavaScript">
var iCallID;
function init()
{
service.useService
("http://myserver.com/services/myservice.asmx?WSDL",
"servicename");
}
function onmyresult()
{
if ((event.result.error)&&(iCallID==event.result.id))
{
var xfaultcode = event.result.errorDetail.code;
var xfaultstring = event.result.errorDetail.string;
var xfaultsoap = event.result.errorDetail.raw;
// Add code to output error information here
alert("Error ");
}
else
{
service.innerHTML= "The method returned the result: "
+ event.result.value;
}
}
</script>
</HEAD>
<body onload="init();">
<BR>
Enter a Value <input type='text' id='param1'>
<BR>
<button onclick='iCallID = service.servicename.callService
("ProcedureName", param1.value);'>Call A Web Method</button>
<div id="service"
style="behavior:url(webservice.htc)"
onresult="onmyresult();">
</div>
</body>
</html>
source: http://weblogs.asp.net/Varad/archive/2004/06/14/155671.aspx