Where part of an aspx file the below script must be put?

<script language="javascript" type="text/javascript">
    am = "This function is disabled!";
    bV  = parseInt(navigator.appVersion)
    bNS = navigator.appName=="Netscape"
    bIE = navigator.appName=="Microsoft Internet Explorer"

    function nrc()
    {
       if (bIE && (event.button >1)) 
       {
          alert(am);
          return false;
       } 
    }
    document.onmousedown=nrc;
    if(bNS && bV<5) window. önmousedown=nrc;
    </script>