SharePoint Lookup field issue

Client has asked to show hide SharePoint lookup fields those contains more than 20+ items.
On my List New Item page there are two fields which needs to be handled.
The issue coming when hiding one lookup and chaging the filed value of different lookup.
Now when showing hidden lookup, The events are not working also I am not able to select/input any item

Please follow this link to follow the behavior of SharePoint Lookup in descriptive way.

Then I found this  great article, Which chanage the lookup to normal lookup that contains 20+ Items:


<script>
$(document).ready(function () {

// Name of the column (Display Name)
var columnName = "Lookup";

// Override the Drop Down List
OverrideDropDownList(columnName);

// Main Function
function OverrideDropDownList(columnName) {

// Construct a drop down list object
var lookupDDL = new DropDownList(columnName);

// Do this only in complex mode...
if (lookupDDL.Type == "C") {

// Hide the text box and drop down arrow
lookupDDL.Obj.css('display', 'none');
lookupDDL.Obj.next("img").css('display', 'none');

// Construct the simple drop down field with change trigger
var tempDDLName = "tempDDLName_" + columnName;
if (lookupDDL.Obj.parent().find("select[ID='" + tempDDLName + "']").length == 0) {
lookupDDL.Obj.parent().append("<select name='" + tempDDLName + "' id='" + tempDDLName + "' title='" + tempDDLName + "'></select>");

lookupDDL.Obj.parent().find("select[ID='" + tempDDLName + "']").bind("change", function () {
updateOriginalField(columnName, tempDDLName);
});
}

// Get all the options
var splittedChoices = lookupDDL.Obj.attr('choices').split("|");

// get selected value
var hiddenVal = $('input[name=' + lookupDDL.Obj.attr("optHid") + ']').val()
if (hiddenVal == "0") {
hiddenVal = lookupDDL.Obj.attr("value")
}

// Replacing the drop down object with the simple drop down list
lookupDDL = new DropDownList(tempDDLName);

// Populate the drop down list
for (var i = 0; i < splittedChoices.length; i++) {
var optionVal = splittedChoices[i];
i++;
var optionId = splittedChoices[i];

var selected = (optionId == hiddenVal) ? " selected='selected'" : "";
lookupDDL.Obj.append("<option" + selected + " value='" + optionId + "'>" + optionVal + "</option>");
}
}
}

// method to update the original and hidden field.
function updateOriginalField(child, temp) {
var childSelect = new DropDownList(child);
var tempSelect = new DropDownList(temp);

// Set the text box
childSelect.Obj.attr("value", tempSelect.Obj.find("option:selected").val());

// Get Hidden ID
var hiddenId = childSelect.Obj.attr("optHid");

// Update the hidden variable
$('input[name=' + hiddenId + ']').val(tempSelect.Obj.find("option:selected").val());
}

// just to construct a drop down box object. Idea token from SPServces
function DropDownList(colName) {
// Simple - when they are less than 20 items
if ((this.Obj = $("select[Title='" + colName + "']")).html() != null) {
this.Type = "S";
// Compound - when they are more than 20 items
} else if ((this.Obj = $("input[Title='" + colName + "']")).html() != null) {
this.Type = "C";
// Multi-select: This will find the multi-select column control on English and most other languages sites where the Title looks like 'Column Name possible values'
} else if ((this.Obj = $("select[ID$='SelectCandidate'][Title^='" + colName + " ']")).html() != null) {
this.Type = "M";
// Multi-select: This will find the multi-select column control on a Russian site (and perhaps others) where the Title looks like 'Выбранных значений: Column Name'
} else if ((this.Obj = $("select[ID$='SelectCandidate'][Title$=': " + colName + "']")).html() != null) {
this.Type = "M";
} else
this.Type = null;
} // End of function dropdownCtl
});
</script>