ASP.NET

<br />
'On code behind page<br />
ddlBusinessLinesL1.Attributes.Add("onchange", "javascript:return DisableBLPostBack('" & ddlBusinessLinesL1.ClientID & "','" & ddlReportType.ClientID & "')")<br />
<br />
'the javascript<br />
function DisableBLPostBack(ddlb,rpType)<br />
    {<br />
        var ddlbus=document.getElementById(ddlb);<br />
        var ddl=document.getElementById(rpType);<br />
        alert(ddlbus.id);<br />
        if (ddl.value==1)<br />
        {<br />
            alert('false');<br />
            return false;<br />
            }<br />
        else <br />
        {<br />
            alert('true');<br />
            return true;<br />
         }     <br />
    }<br />