<a id="ahrefAfter" href="javascript:getvalue( <%=HdnsmallImageAfter.ClientID%>.value);" runat="server" title="AFTER">ABC</a>
or 
<a id="ahrefAfter" href="javascript:getvalue( <%=HdnsmallImageAfter.ClientID%>);" runat="server" title="AFTER">ABC</a>

function getvalue(id)
{
var txt=document.getElementById(id);
 if(txt.value == "abc")
{
}
}

在文本框上调用JS函数.为此，请使用以下代码:

Hi, call JS function on textbox. use below code for this:

<a id="ahrefAfter" href="javascript:void(0);" onclick="javascript:getvalue();" runat="server" title="AFTER">ABC</a>

JS函数

JS Function

function getvalue()
{
hdnObj = document.getElementById('<%=HiddenField.ClientID%>');
alert(hdnObj.value);
}

这对我有效:

This Is Working For ME:

<asp:hiddenfield id="HdnsmallImageAfter" value="abc" runat="server" xmlns:asp="#unknown" />
<a id="ahrefAfter" href="javascript:getvalue(HdnsmallImageAfter.value);" runat="server" title="AFTER">ABC</a>

function getvalue(v) {

       if (v == "abc") {
           alert("HI");
       }
   }