In one of my old post, I have already explained that how to generate JSON in Visualforce page. So Considering same article I have create Visualforce page named “Account_JSON” which returns list of Accounts on basis of text entered in input field.

Live Demo :

try searching “gen” or “edg” and spacebar, It will load account after one space.

Visualforce Account_JSON :

<apex:page Controller="AccountJSONCreator" contentType="application/x-JavaScript; charset=utf-8" showHeader="false" standardStylesheets="false" sidebar="false">
{!JSON}
</apex:page>

Controller AccountJSONCreator :

public with sharing class AccountJSONCreator {

    public String getJSON()
    {
        String AccountName = Apexpages.currentPage().getParameters().get('AccName');
        List<AccountWrapper> wrp = new List<AccountWrapper>();
        for (Account a : [Select a.Id, a.Website, a.Name, a.BillingCountry, a.BillingCity
                            From
                                Account a
                            WHERE Name Like : '%'+AccountName+'%' ]) {
               AccountWrapper w = new AccountWrapper (a.Name, nullToBlank (a.BillingCountry), nullToBlank (a.BillingCity));
               wrp.add(w);
            }
        return JSON.serialize(wrp);
    }

    public String nullToBlank(String val)
    {
        return val == null ?'':val;
    }

    public class AccountWrapper
    {
        String AccName,BillingCountry,BillingCity;

        public AccountWrapper(String aName, String bCountry, String bCity)
        {
            AccName = aName;
            BillingCountry = bCountry;
            BillingCity = bCity;
        }
    }

    static testMethod void AccountJSONCreatorTest() {
        AccountJSONCreator obj = new AccountJSONCreator();
        obj.getJSON();
    }
}

Now let’s create a Component which will make AJAX request to above visualforce page “Account_JSON” and Parse JSON page using JQuery.

Component Autocomplete_Component :

<apex:component>
 <apex:attribute name="ComponentLabel" description="Label of Component"
                    type="String" required="true"/>

<apex:stylesheet value="{!URLFOR($Resource.AutoCompleteWithModal, '/JQueryUI/css/ui-lightness/jquery-ui-1.8.17.custom.css')}"/>
<apex:includeScript value="{!URLFOR($Resource.AutoCompleteWithModal, '/JQueryUI/js/jquery-1.7.1.min.js')}"/>
<apex:includeScript value="{!URLFOR($Resource.AutoCompleteWithModal, '/JQueryUI/js/jquery-ui-1.8.17.custom.min.js')}"/>
<apex:stylesheet value="{!URLFOR($Resource.AutoCompleteWithModal, '/JQueryModal/css/basic.css')}"/>

<style type="text/css">
    .ui-autocomplete-loading { background: white url('{!URLFOR($Resource.AutoCompleteWithModal, 'AjaxLoad.gif')}') right center no-repeat; }
</style>

{!ComponentLabel} <apex:inputText id="theTextInput"/>

<script type="text/javascript">
//$ac - AutoComplete

$ac = jQuery.noConflict();

function getLoadingImage()
{
    var loadImagURL = "{!URLFOR($Resource.AutoCompleteWithModal, 'BigLoad.gif')}";
    var retStr = ['<img src="', loadImagURL ,'" title="loading..." alt="loading..." class="middleAlign" />'];
    return retStr.join("");
}

var sourcePage = 'https://c.ap1.visual.force.com/apex/Account_JSON?core.apexpages.devmode.url=0';

 $ac(function() {
        var txtVal =  $ac('[id="{!$Component.theTextInput}"]');
        //This method returns the last character of String
        function extractLast(term) {
            return term.substr(term.length - 1);
        }

        $ac('[id="{!$Component.theTextInput}"]').autocomplete({
            source: function( request, response ) {

                //Abort Ajax
                var $this = $ac(this);
                var $element = $ac(this.element);
                var jqXHR = $element.data('jqXHR');
                if(jqXHR)
                    jqXHR.abort();

                $ac('[id="{!$Component.theTextInput}"]').addClass('ui-autocomplete-loading');
                //prompt('',sourcePage+'&key='+txtVal.val());
                $element.data('jqXHR',$ac.ajax({
                    url: sourcePage+'&AccName='+txtVal.val(),
                    dataType: "json",
                    data: {
                    },
                    success: function( data ) {
                        response( $ac.map( data , function( item ) {
                            return {
                                label: '<a>'+
                                item.AccName+"<br />"+
                                '<span style="font-size:0.8em;font-style:italic">'
                                +item.BillingCity+', '+item.BillingCountry+
                                "</span></a>",
                                value: item.AccName
                            }
                        }));
                    },
                    complete: function() {

                        //This method is called either request completed or not
                        $this.removeData('jqXHR');

                        //remove the class responsible for loading image
                        $ac('[id="{!$Component.theTextInput}"]').removeClass('ui-autocomplete-loading');
                    }
                })
                );

            },
            search: function() {
                /*
                // If last character is space
                    var term = extractLast(this.value);
                    if(term == " ")
                    {
                        return true;
                    }
                */

                //If String contains at least 1 space
                if (this.value.indexOf(" ") >= 0)
                {
                    $ac('[id="{!$Component.theTextInput}"]').autocomplete('option', 'delay', 500);
                    return true;
                }
                return false;
            },
            focus: function() {
                // prevent value inserted on focus
                return false;
            },
            select: function(event, ui) {
                var selectedObj = ui.item;
                //alert(selectedObj.compId);
                //getCompanyDetail(selectedObj.compId);
                return true;
            }
        }).data("autocomplete")._renderItem = autoCompleteRender;

    });

function autoCompleteRender(ul, item) {
    return $ac("<li></li>").data("item.autocomplete", item).append(item.label).appendTo(ul);
}

</script>
</apex:component>

Now Visualforce page, which will host above Component.

Viusalforce Page : AutoCompleteDemo

<apex:page >
    <apex:form >
        <c:autocomplete_component ComponentLabel="Enter Account Name : "/>
    </apex:form>
</apex:page>

Download Static resource – AutoCompleteWithModal