How can you call Apex class using Javascript ? Give Example

 How can you call Apex class using Javascript ? Give Example

global class myClass {

                webService static Id makeContact (String lastName, Account a) {

                                Contact c = new Contact(LastName = lastName, AccountId = a.Id);

                                Insert c;

                                return c.id;

                }

}

we can execute above method from javascript like :

var account = sforce.sObject("Account");

var id = sforce.apex.execute("myClass“ , "makeContact",

{lastName:"Smith", a:account});

To call a webService method with no parameters, use {} as the third parameter for sforce.apex.execute .

Also, you can use the following line to display a popup window with debugging information:

sforce.debug.trace=true;