Insertion into a LookUp Column using ECMA Script

var myColl="";
var strCurrentWeb="";
var strCurrentSiteUrl="";
function BindLookUpData()
{
    try
    {
        var context = new SP.ClientContext.get_current();
        var web = context.get_web();
        strCurrentWeb=context.get_url();
        strCurrentSiteUrl=window.location.protocol + '//' + window.location.host + strCurrentWeb;
        var list = web.get_lists().getByTitle('Book Category');
        var sQuery="<View><Query><OrderBy><FieldRef Name='ID' /></OrderBy></Query></View>";
        var camlQuery = new SP.CamlQuery();
        camlQuery.set_viewXml(sQuery);
        this.myColl = list.getItems(camlQuery);
        context.load(this.myColl, 'Include(Title, ID)');
        context.executeQueryAsync(Function.createDelegate(this, this.BindLookUpDataSuccess), Function.createDelegate(this, this.BindLookUpDataFailed));
    }
    catch(Ex)
    {
        alert(Ex);
    }
}

function BindLookUpDataSuccess()
{
    var strBookNames="";
    if(myColl.get_count()!=0)
    {
        var listEnumerator = this.myColl.getEnumerator();
        strBookNames+="<Select id='ddlCategory' width='158px'>";
        strBookNames+="<Option>Select Category</Option>";
        while (listEnumerator.moveNext())
        {
            var item = listEnumerator.get_current();
            var strItemID=item.get_item('ID');
            var strTitle=item.get_item('Title');
            strBookNames+="<Option Value='"+strItemID+"'>"+strTitle+"</Option>";
        }
        strBookNames+="</Select>";
    }
    document.getElementById("tdCategory").innerHTML=strBookNames;  
}

function BindLookUpDataFailed(sender, args)
{
    alert('failed. Message:' + args.get_message());
}

function BindData()
{
    ExecuteOrDelayUntilScriptLoaded(BindLookUpData, "sp.js");
}

function SaveLookUpColumn()
{
        debugger;
        var context = new SP.ClientContext.get_current();
        var web = context.get_web();
        strCurrentWeb=context.get_url();
        strCurrentSiteUrl=window.location.protocol + '//' + window.location.host + strCurrentWeb;
        var list = web.get_lists().getByTitle('Book Names');
        var listItemCreationInfo = new SP.ListItemCreationInformation();
        var newItem = list.addItem(listItemCreationInfo);
        newItem.set_item('Title', document.getElementById("txtBookName").value);
        var _newLookupField = new SP.FieldLookupValue();
        _newLookupField.set_lookupId($("#ddlCategory").val());
        newItem.set_item('Category', _newLookupField);
        newItem.update();
        context.executeQueryAsync(Function.createDelegate(this, this.LookUpInsertSuccess), Function.createDelegate(this, this.LookUpInsertFailed));
}

function LookUpInsertSuccess()
{
    alert('LookUp Column Successfuly Inserted');
    document.getElementById("txtBookName").value="";
    $("select#ddlCategory").get(0).selectedIndex=0;
}

function LookUpInsertFailed(sender, args)
{
    alert('failed. Message:' + args.get_message());
}

function InsertLookUpColumn()
{
    ExecuteOrDelayUntilScriptLoaded(SaveLookUpColumn, "sp.js");
}

_spBodyOnLoadFunctionNames.push("BindData");