global class remotingexample
{
    public String accountName { get; set; }
    public static Account account { get; set; }
    public remotingexample() { }
   
    @RemoteAction
    webservice static Account getAccount(String accountName)
    {
        account = [select id, name from Account where name=:accountName ];
        return account;
    }
}

<apex:page controller="remotingexample">
    <script type="text/javascript">
    function getAccountJS()
    {
        var accountNameJS = document.getElementById('accName').value;       
        sample.getAccount( accountNameJS,
        function(result, event)
        {
            if (event.status)
            {
                // demonstrates how to get ID for HTML and Visualforce tags
                document.getElementById("{!$Component.theBlock.thePageBlockSection.theFirstItem.accId}").innerHTML = result.Id;
                document.getElementById("{!$Component.theBlock.thePageBlockSection.theSecondItem.accNam}").innerHTML = result.Name;
            }
            else if (event.type === 'exception')
            {
                document.getElementById("errors-js").innerHTML = event.message;
            } else
            {
                document.getElementById("errors-js").innerHTML = event.message;
            }
        }, {escape:true});
    }
    </script>
    Account Name :<input id="accName" type="text" />
    <button onclick="getAccountJS()">Get Account</button>
    <div id="errors-js"> </div>
    <apex:pageBlock id="theBlock">
        <apex:pageBlockSection id="thePageBlockSection" columns="2">
            <apex:pageBlockSectionItem id="theFirstItem">
                <apex:outputText id="accId"/>
            </apex:pageBlockSectionItem>
            <apex:pageBlockSectionItem id="theSecondItem" >
                <apex:outputText id="accNam" />
            </apex:pageBlockSectionItem>
        </apex:pageBlockSection>
    </apex:pageBlock>
</apex:page>

// 1. apex class to handle server side methods
public class ContactController 
{
   @AuraEnabled  
   public static List<Contact> FindAll()
   {
      return [select ID,Name,Phone from Contact LIMIT 20];
   }
   
    //Get contacts based on Contact Name
    @AuraEnabled
    public static List<Contact> FindByName(String searchKey)
   {
      String name='%'+searchKey+'%';
       return [select ID,Name,Phone from Contact where Name LIKE:name LIMIT 100];
   }
    
    //Get contacts based on Contact ID, single record
    @AuraEnabled
    public static Contact FindByID(String conID)
   {
      return [select ID,Name,Account.Name,Phone from Contact where ID=:conID LIMIT 100];
   }
}

// 2 lightning component : contactList_comp
<aura:component controller="ContactController">
    
	<aura:attribute name="contacts1"
                    type="Contact[]"/>  
    
    <aura:handler name="init"
                  value="{!this}"
                  action="{!c.doInit}"/>
    
    <ul class="list-group">
        <aura:iteration items="{!v.contacts1}"
                        var="con">
        <li class="list-group-item">
            <a href="{!'#con/'+con.ID}">
                <p>{!con.Name}</p>
                <p>{!con.Phone}</p>
            </a>
        </li>
   </aura:iteration>
    </ul>
</aura:component>

// 3 . client side controller for the component
({
	doInit : function(cmp,event)
    {
	    var action=cmp.get("c.FindAll");
        action.setCallback(this,function(a)
        {
            cmp.set("v.contacts1",a.getReturnValue());
                        
        });
        $A.enqueueAction(action);
  	},
    
    searchkeychange : function(cmp,event,helper)
    {
	    var search_key=event.getParam("c.searchkey1");
        var action=cmp.get("c.FindByName");
        
        action.setParams({"search_key":searchkey1});
        
        action.setCallback(this,function(a)
        {
           cmp.set("v.contacts1",a.getReturnValue());
        });
        $A.enqueueAction(action);
	}
})

//4 search bar component
<aura:component >
	<input type="text"
           class="form-control"
           onkeyup="{!c.searchkeychange}"
           placeholder="Enter contact Name">
    </input>
</aura:component>

//5 client side controller for search bar component
({
	searchkeychange:function(component,event,helper) 
    {
		var myEvent=$A.get("e.c:searchkeychange"); 
        
        myEvent.setParams({"searchkey1":event.target.value});
       
        myEvent.fire(); 
  	}
})

// 6 event for search bar component
<aura:event type="APPLICATION" 
            description="Event template">

    <aura:attribute name="searchkey1"
                    type="String">
    </aura:attribute>
</aura:event>

//7. Now I create a an application
<aura:application >
    <link href='/resource/bootstrap/' 
          rel="stylesheet">
    </link>
    
    <div class="navbar navbar-default navbar-static-top"
         role="navigation">
    
           <div class="container">
               <div class="navbar-header">
                <a href="#" class="navbar-brand">Lightning Contacts</a>
                   
               </div>
           
           </div>
    </div>
    <div class="container">
        <div class="row">
               <div class="col-sm-12">
                   <c:searchbar_comp />
                   <c:ContactList_comp />
              </div>
                   
        </div>
    </div>    
</aura:application>

public class updateaccountrating
{
  public void updaterating(List<Opportunity> oppor)
  {
    // 1. Get opportunity accountID and store in a list.
    Set<ID> opporAccountID = new Set<ID>();
    
    for(Opportunity o:oppor)
    {
       opporAccountID.add(o.AccountID);
    } 
    
    List<Account> aFinal=new List<Account>();
    
    List<Account> acc=[select ID,rating from account where ID IN :opporAccountID];
    
    for(Opportunity o:oppor)
    {
      for(Account a:acc)
      {
         if (o.StageName == 'Closed Won')
         
             a.rating='Hot';
             aFinal.add(a);
         
      }
     
    }
    
    if (aFinal.size() > 0 && aFinal != NULL)
       Database.Insert(aFinal,false);
    }
}

trigger trg_updateaccountrating on Opportunity (before Insert,before Update)
{
  if (trigger.IsBefore)
  {
    if (trigger.IsUpdate)
    { 
     updateaccountrating a = new updateaccountrating();
     a.updaterating(Trigger.New);
    }
  }

}

// 1. apex class to handle server side methods
public class ContactController 
{
   @AuraEnabled  
   public static List<Contact> FindAll()
   {
      return [select ID,Name,Phone from Contact LIMIT 20];
   }
   
    //Get contacts based on Contact Name
    @AuraEnabled
    public static List<Contact> FindByName(String searchKey)
   {
      String name='%'+searchKey+'%';
       return [select ID,Name,Phone from Contact where Name LIKE:name LIMIT 100];
   }
    
    //Get contacts based on Contact ID, single record
    @AuraEnabled
    public static Contact FindByID(String conID)
   {
      return [select ID,Name,Account.Name,Phone from Contact where ID=:conID LIMIT 100];
   }
}

// 2 lightning component : contactList_comp
<aura:component controller="ContactController">
    
	<aura:attribute name="contacts1"
                    type="Contact[]"/>  
    
    <aura:handler name="init"
                  value="{!this}"
                  action="{!c.doInit}"/>
    
    <ul class="list-group">
        <aura:iteration items="{!v.contacts1}"
                        var="con">
        <li class="list-group-item">
            <a href="{!'#con/'+con.ID}">
                <p>{!con.Name}</p>
                <p>{!con.Phone}</p>
            </a>
        </li>
   </aura:iteration>
    </ul>
</aura:component>

// 3 . client side controller for the component
({
	doInit : function(cmp,event)
    {
	    var action=cmp.get("c.FindAll");
        action.setCallback(this,function(a)
        {
            cmp.set("v.contacts1",a.getReturnValue());
                        
        });
        $A.enqueueAction(action);
  	},
    
    searchkeychange : function(cmp,event,helper)
    {
	    var search_key=event.getParam("c.searchkey1");
        var action=cmp.get("c.FindByName");
        
        action.setParams({"search_key":searchkey1});
        
        action.setCallback(this,function(a)
        {
           cmp.set("v.contacts1",a.getReturnValue());
        });
        $A.enqueueAction(action);
	}
})

//4 search bar component
<aura:component >
	<input type="text"
           class="form-control"
           onkeyup="{!c.searchkeychange}"
           placeholder="Enter contact Name">
    </input>
</aura:component>

//5 client side controller for search bar component
({
	searchkeychange:function(component,event,helper) 
    {
		var myEvent=$A.get("e.c:searchkeychange"); 
        
        myEvent.setParams({"searchkey1":event.target.value});
       
        myEvent.fire(); 
  	}
})

// 6 event for search bar component
<aura:event type="APPLICATION" 
            description="Event template">

    <aura:attribute name="searchkey1"
                    type="String">
    </aura:attribute>
</aura:event>

//7. Now I create a an application
<aura:application >
    <link href='/resource/bootstrap/' 
          rel="stylesheet">
    </link>
    
    <div class="navbar navbar-default navbar-static-top"
         role="navigation">
    
           <div class="container">
               <div class="navbar-header">
                <a href="#" class="navbar-brand">Lightning Contacts</a>
                   
               </div>
           
           </div>
    </div>
    <div class="container">
        <div class="row">
               <div class="col-sm-12">
                   <c:searchbar_comp />
                   <c:ContactList_comp />
              </div>
                   
        </div>
    </div>    
</aura:application>

<apex:page >
<style>
.dropbtn {
    background-color: #4CAF51;
    color: blue;
    padding: 16px;
    font-size: 10px;
    border: none;
    cursor: pointer;
}

.dropdown {
    position: relative;
    display: inline-block;
}
.dropdown-content {
    display: none;
    position: absolute;
    right: 0;
    background-color: #f9f9f0;
    min-width: 160px;
    box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
}
.dropdown-content a {
    color: black;
    padding: 12px 16px;
    text-decoration: none;
    display: block;
}
.dropdown-content a:hover {background-color: #f1f1f1}
.dropdown:hover .dropdown-content
{
    display: block;
}
.dropdown:hover .dropbtn
{
    background-color: #3e8e41;
}
</style>

<div class="dropdown" style="float:right;">
  <button class="dropbtn">Quick Access Menu</button>
  <div class="dropdown-content">
    <a href="#">Link 1</a>
    <a href="#">Link 2</a>
    <a href="#">Link 3</a>
  </div>
</div>

</apex:page>