Access a listitem of a master page form child page by id

Question

I created a master page where i added a listitem , i,e ; 

<li ><a href="#" onclick="fProposal()" id="home" > Home </a> </li>

 

 

function fProposal() {

debugger;

document.getElementById("LookupId").href = "/Lookups/Lookups.aspx?Id=LookupId";

}

 

this in maste page with javascript 

 =======================??????????????===========================

Now i want to access this id form a child page and want to add the css proparty.

i did this one,

 

 =======================================================

string v = Request.QueryString["Id"]; 

// ContentPlaceHolder cph = (ContentPlaceHolder)this.Master.FindControl("ContentPlaceHolder1");

// HtmlControl li = (HtmlGenericControl)cph.FindControl(v);

// HtmlControl li = (HtmlGenericControl)FindControl("UpdatePanel1");

// li.Attributes.Add("class", "active");

//if (li != null)

// this.hide.style.Add("display", "none");

 

this is the child page where i want to change... 

 =============================================================

but it is completely error ...

can any one help me....plz ???