How call c# method use javascript in html page

Question

Hello

How call c# method use javascript in html page

I have method  LoadXml("http://localhost/mysite/res/toolbar.xml") and need this method call in html page use javascript.

Example:

<script type="text/javascript">
myToolbar.LoadXml("http://localhost/mysite/res/toolbar.xml");
</script>

How call?  Please, help