How to: Create fields in sharepoint list using ECMAScript

By using below code we can create fields of different types using ECMAScript:

function createFields()
{
   currentcontext = new SP.ClientContext.get_current();
   web = clientContext.get_web();
   this.list = web.get_lists().getByTitle(‘ListName’);  
 //Add new fields to the list

//Single line of text Field
this.newColumn = oList.get_fields().addFieldAsXml("", true,
    SP.AddFieldOptions.defaultValue);
 
//Multi line of text Field
this.newColumn = oList.get_fields().addFieldAsXml("", true,
    SP.AddFieldOptions.defaultValue);
 
//Boolean Field
this.newColumn = oList.get_fields().addFieldAsXml("", true,
    SP.AddFieldOptions.defaultValue);

//Number Field
this.newColumn = oList.get_fields().addFieldAsXml("", true,
    SP.AddFieldOptions.defaultValue);

//DateTime Field
this.newColumn = oList.get_fields().addFieldAsXml("", true,
  SP.AddFieldOptions.defaultValue);

//People Picker Field
this.newColumn = oList.get_fields().addFieldAsXml("", true,
  SP.AddFieldOptions.defaultValue);

//Choice field(dropdown)
 this.newColumn= oList.get_fields().addFieldAsXml("ChoiceAChoiceAChoiceBChoiceCChoiceD", true, 
  SP.AddFieldOptions.defaultValue);
 
 currentcontext.load(this.newfield);
 currentcontext.executeQueryAsync(Function.createDelegate(this, this.onListCreateSuccess), Function.createDelegate(this, this.onQueryFailed));
}

function onListCreateSuccess(sender, args) {alert('sucess');
    alert("Field Name: " + this.newfield.get_title());
}
 
function onQueryFailed(sender, args) {
 alert('request failed ' + args.get_message() + '\n' + args.get_stackTrace());
}

Note: SP.Field.typeAsString Property is used to Gets or sets a value that specifies the type of the field.[From Msdn:http://msdn.microsoft.com/en-us/library/ee553500.aspx]