Use this to fire list workflows by name or subscriptionId.

$sp.wf.js

/*!
 * Created by Matthew Bramer
 * Released under the MIT license
 * Date: 2015-04-18
 * Props to: http://plumsail.com/blog/2015/02/start-sharepoint-2013-workflows-selected-items/
 * Tested using SharePoint Online.
 * On-Prem still needs testing.
 */

window.$sp = window.$sp || {};
window.$sp.wf = (function( $, undefined ) {
    "use strict";
    var ctx,
        web,
        wfManager,
        JS_SUFFIX = ".js",
        SP_WORKFLOW_SERVICES = "SP.WorkflowServices",
        SP_WORKFLOW_SERVICES_SCRIPT_NAME = SP_WORKFLOW_SERVICES + JS_SUFFIX,
        risGuid = /[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}/i,
        oDataHeader = "application/json;odata=verbose",
        initializeVariables = function() {
            ctx = SP.ClientContext.get_current();
            web = ctx.get_web();
            wfManager = SP.WorkflowServices.WorkflowServicesManager.newObject( ctx, web );
        },
        registerWFscripts = function() {
            SP.SOD.registerSod(
                SP_WORKFLOW_SERVICES_SCRIPT_NAME,
                SP.Utilities.Utility.getLayoutsPageUrl( SP_WORKFLOW_SERVICES + JS_SUFFIX )
            );
            SP.SOD.executeFunc(
                SP_WORKFLOW_SERVICES_SCRIPT_NAME,
                SP_WORKFLOW_SERVICES + ".WorkflowServicesManager",
                initializeVariables
            );
        },
        init = function() {
            SP.SOD.executeFunc(
                "sp" + JS_SUFFIX,
                "SP.ClientContext",
                registerWFscripts
            );
        },
        set_errorHandler = function( func ) {
            errorHandler = func;
        },
        errorHandler = function( sender, args ) {
            var message = this,
                spError = args && args.get_message,
                restAPIError = sender && sender.responseText

            ;

            if( this.id ) {
                message += " on item with ID: " + this.id;
            }

            SP.UI.Notify.addNotification( message, false );
            console.log( message );

            if( spError ) {
                console.log( "Error:", args.get_message(), "\nStackTrace:", args.get_stackTrace() );
            }

            if( restAPIError ) {
                console.log( restAPIError );
            }
        },
        set_successHandler = function( func ) {
            successHandler = func;
        },
        successHandler = function( sender, args ) {
            var wfName = this.name || this.subscription && this.subscription.get_name(),
                message = "Workflow " + wfName + " has started."

            ;

            if( this.id ) {
                message = message.replace(".", "");
                message += " on this item. ID: " + this.id;
            }

            SP.UI.Notify.addNotification( message, false );
        },
        fireWfByName = function( sender, args ) {
            var subscription = this.subscription,
                id = this.id,
                initiationParams = this.initiationParams || {},
                workflows = subscription.getEnumerator(),
                workflow,
                foundWrkFlow = false

            ;

            while( workflows.moveNext() ) {
                workflow = workflows.get_current();

                if( workflow.get_name() === this.name ) {
                    startWorkflow({
                        subscriptionId: workflow.get_id(),
                        id: id,
                        initiationParams: initiationParams
                    });

                    foundWrkFlow = true;
                    break;
                }
            }

            if( !foundWrkFlow ) {
                errorHandler.call( "Could not find workflow named: " + this.name );
            }
        },
        fireWfBySubscription = function( sender, args ) {
            var subscription = this.subscription,
                id = this.id,
                initiationParams = this.initiationParams || {},
                wfInstance = wfManager.getWorkflowInstanceService()

            ;

            // https://msdn.microsoft.com/en-us/library/office/microsoft.sharepoint.client.workflowservices.workflowinstanceservice_methods.aspx

            if( id ) {
                wfInstance.startWorkflowOnListItem( subscription, id, initiationParams );
            } else {
                wfInstance.startWorkflow( subscription, initiationParams );
            }

            ctx.executeQueryAsync(
                successHandler.bind( this ),
                errorHandler.bind( "Could not fire workflow. SubscriptionId: " + this.subscriptionId )
            );
        },
        startWorkflow = function( opt ) {
            var subscriptionService = wfManager.getWorkflowSubscriptionService(),
                success,
                error

            ;

            // different methods to fire workflows with 2013.
            // https://msdn.microsoft.com/en-us/library/microsoft.sharepoint.workflowservices.workflowsubscriptionservice_members.aspx
            if( opt.subscriptionId ) {
                opt.subscription = subscriptionService.getSubscription( opt.subscriptionId );
                ctx.load( opt.subscription );
                success = fireWfBySubscription.bind( opt );
                error = errorHandler.bind( "Failed to load subscription: " + opt.subscriptionId );
            } else {
                opt.subscription = subscriptionService.enumerateSubscriptions();
                ctx.load( opt.subscription );
                success = fireWfByName.bind( opt );
                error = errorHandler.bind( "Failed to load workflow subscriptions." );
            }

            ctx.executeQueryAsync(
                success,
                error
            );
        },
        removeDemCurlies = function( v ) {
            return v.replace( /{|}/g, "" );
        },
        getListItemDeets = function( listUrl ) {
            return $.ajax({
                type: "GET",
                url: listUrl,
                dataType: "json",
                headers: {
                    "Accept": oDataHeader,
                    "Content-Type": oDataHeader
                }
            });
        },
        fire2010Workflow = function( data ) {
            var success,
                listGuid = data.d.__metadata.uri.match( risGuid )[ 0 ],
                itemId = data.d.GUID
            ;

            this.result = this.subscriptionService.startWorkflow( this.name, null, listGuid, itemId, this.initiationParams );
            success = successHandler.bind( this );

            ctx.executeQueryAsync(
                success,
                this.error
            );
        },
        start2010Workflow = function( opt ) {
            var subscriptionService = wfManager.getWorkflowInteropService(),
                wfName = opt.name,
                id = opt.id,
                itemGuid,
                initiationParams = opt.initiationParams,
                queryPrefix = "/_api/web/lists",
                querySuffix = "/items(" + id + ")?$select=GUID",
                // May need to do this later when ctx is dynamic.
                // listUrl = web.get_url(),
                listUrl = _spPageContextInfo.webAbsoluteUrl + queryPrefix,
                listGuid,
                errorMessage = "Failed to fire 2010 {0} Workflow.",
                success,
                error

            ;

            // Fire 2010 workflows!
            // https://msdn.microsoft.com/en-us/library/office/microsoft.sharepoint.client.workflowservices.interopservice.startworkflow.aspx

            // Not sure if opt.result is going to be helpful, but leaving it here for the meantime.
            // If it is useful, then I'll bind it to the both handlers.
            // If not, I'll drop it altogether.
            if( id ) {
                listGuid = opt.list.match( risGuid );
                if( listGuid ) {
                    listGuid = removeDemCurlies( listGuid[ 0 ] );
                    listUrl += "(guid'" + listGuid + "')";
                } else {
                    listUrl += "/GetByTitle('" + opt.list + "')";
                }

                listUrl += querySuffix;

                // converts numbers to strings.
                id = id + "";
                itemGuid = id.match( risGuid );

                if( listGuid && itemGuid ) {
                    // List GUID and item GUID were provided, no need for API call.
                    opt.result = subscriptionService.startWorkflow( wfName, null, listGuid, itemGuid[ 0 ], initiationParams );
                    success = successHandler.bind( opt );
                    error = errorHandler.bind( errorMessage.replace("{0}", "Site") );
                } else {
                    // Need to resolve List GUID and get the item GUID.
                    opt.subscriptionService = subscriptionService;
                    opt.error = errorHandler.bind( errorMessage.replace("{0}", "List") );

                    return getListItemDeets.bind( opt )( listUrl )
                        .then( fire2010Workflow.bind( opt ), opt.error );
                }
            } else {
                // Site WF
                opt.result = subscriptionService.startWorkflow( wfName, null, null, null, initiationParams );
                success = successHandler.bind( opt );
                error = errorHandler.bind( errorMessage.replace("{0}", "Site") );
            }

            ctx.executeQueryAsync(
                success,
                error
            );
        }

    ;


    init();

    // TODO:
    // On-Prem testing.
    // Look at custom events.
    // https://msdn.microsoft.com/en-us/library/office/dn481315.aspx
    // Add promises.
    return {
        set_errorHandler: set_errorHandler,
        set_successHandler: set_successHandler,
        startWorkflow: startWorkflow,
        start2010Workflow: start2010Workflow
    };
}( window.jQuery ));


/*
 * Usage
 * via subscriptionId or Workflow Name. Preferably the latter.
*/

// List bound WF fired by Workflow Name, Muy bien!
$sp.wf.startWorkflow({
    name: "Send Email",
    id: 1,
    initiationParams: {
        EasyText: "What's up?",
        // `Here I Am` is the real initation parameter name. Note the spaces.
        HereIam: "<p><b>heyo!</b></p><p>otra ves</p>"
    }
});

// Site workflows! YaY!
$sp.wf.startWorkflow({
    name: "Site WF",
    initiationParams: {
        WooP: "<b>That's what's up!</b>"
    }
});

// 2010 Site WF!
$sp.wf.start2010Workflow({
    name: "Site WF - 2010",
    initiationParams: {
        // `Something with Spaces` is the real initation parameter name. Note the spaces and casing.
        SomethingwithSpaces: "<b>That's what's up!</b>"
    }
});

// 2010 List Bound WF.
$sp.wf.start2010Workflow({
    name: "SendEmail2010",
    list: "Test",
    id: 1,
    initiationParams: {
        "ThingsChangePeopleChange": "<b>Used list display name and item id.</b>"
    }
});

$sp.wf.start2010Workflow({
    name: "SendEmail2010",
    list: "{FD21AC5B-15D9-443A-B7A5-1FB6A2AF667D}",
    id: 1,
    initiationParams: {
        "ThingsChangePeopleChange": "<b>Used list GUID and item id.</b>"
    }
});

$sp.wf.start2010Workflow({
    name: "SendEmail2010",
    list: "{FD21AC5B-15D9-443A-B7A5-1FB6A2AF667D}",
    id: "{211ffdfc-69c5-4206-917d-befe62a6ffb4}",
    initiationParams: {
        "ThingsChangePeopleChange": "<b>Used list GUID and item GUID. Prevents a call to SP's REST API.</b>"
    }
});

// The ugly duckling...  Don't use this, please. :)
// Via Subscription ID, YUCK!
$sp.wf.startWorkflow({
    subscriptionId: "{CE3890BC-3361-4F1C-9036-40A07E0EC449}",
    id: 1
});