Start Site Workflow using webservice and javascript Button

if your workflow doesn't request for any inputs you need not to care about association data.

to add a buton on page, add a script editor or html form webpart on the page. configure a HTML snippet for the webpart that creates a button and calls a javascript when clicked.

Thank you for the response. How can I tell completely if it doesn't require any inputs? Also I'm using the js in that post I linked to. I can just pull out the associationData line?

Thank you for the response. How can I tell completely if it doesn't require any inputs? 

try to start workflow manually and check if there appear some controls on the start form that expect to provide some inputs.

if there are any, you may need to supply respective data within associationData element. but that need not necessarily mean you have to. the workflow may be designed so that if nothing is provided it works with some defaults.

the best would be to discuss that with workflow designer directly.

 I can just pull out the associationData line?

no, associationData element has to be present in the request.

it just means you do not need to provide anything within associationData element body

see documentation how to work with association data

https://help.nintex.com/en-US/sdks/sdk2013/#Operational/SDK_NW_OPS_WorkflowsAssocData.htm

OK so there are no inputs to be provided so I'm leaving the associationData element blank. I'm using the below script to run the javascript
<script type="text/javascript" src="https://MySite.org/Test/PublicForms/SiteAssets/jquery-1.11.1.min.js"></script>
<input type="Button" onclick="https://MySite.org/Test/public/SiteAssets/jQueryLibraries/StartSiteWorkflow.js" value="REFRESH LIST">
</script>
And the StartSiteWorkflow.js is:

function ResetLetter() {
var waitingDialog;
// var waitingDialog = SP.UI.ModalDialog.showWaitScreenWithNoClose('Your action is in progress...', "Please wait while we generate the tasks for you.");
SP.SOD.executeFunc('sp.js', 'SP.ClientContext', function () {
waitingDialog = SP.UI.ModalDialog.showWaitScreenWithNoClose('Your action is in progress...', "Please wait while we generate the tasks for you.");
});

var $request = new Sys.Net.WebRequest();
var siteUrl = "https://MySite.org/Test/public/SiteAssets/public/CommonRequest";
$request.set_url((siteUrl || _spPageContextInfo.webServerRelativeUrl.replace(/^s+|s+$/gi, '')) + "/_vti_bin/NintexWorkflow/Workflow.asmx");
var $headers = $request.get_headers();
$headers["Content-Type"] = "text/xml; charset=utf-8";
$headers["SOAPAction"] = "http://nintex.com/StartSiteWorkflow";
$body = "<?xml version=""1.0"" encoding=""utf-8""?>" +
"<soap:Envelope xmlns:xsi=""http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd=""http://www.w3.org/2001/XMLSchema" xmlns:soap=""http://schemas.xmlsoap.org/soap/envelope/">" +
"<soap:Body>" +
"<StartSiteWorkflow xmlns=""http://nintex.com">" +
"<workflowName>MyWorkflowDashboard</workflowName>" +
"<AssociationData></associationData>" +
"</StartSiteWorkflow>" +
"</soap:Body>" +
"</soap:Envelope>";
var thisArgs = this;
$request.add_completed(function (executor, args) {
var statusCode = executor.get_statusCode();
if (statusCode >= 200 && statusCode <= 399) {
Sys.Debug.trace("Action terminated");
} else {
Sys.Debug.trace('Warning : Error (Status code {0})', statusCode);
alert('Error');
}
waitingDialog.close();
});

Can you see anything I'm missing? Thank you SO much for all of your help by the way.

haven't tested your whole code, but noticed mistake in button click handler - it has to call javascript function directly, not a javascript file.

StartSiteWorkflow.js script has to be included with a script tag, just like you do for jquery

as I said, it has to call js function

<input type="Button" onclick="ResetLetter()" value="REFRESH LIST">

Hi there, the button still isn't working. I did however find a workaround, it's not as elegant but it does work. I created a list with a workflow that does the webservice call to run the site workflow. And the button activates that workflow. A bit cumbersome but it does work. Thanks so so much all of your help.

in between step with list workflow is really not necessary.

i fyou managed to start a list workflow you should be able to start a site one as well. there's not a big difference between the two.

I'm not not whether it's just a copy&paste problem, but your above code doesn't seem to be complete resp. syntactilay correct...

I wish it was even that elegant! The "button" is actually an Infopath form that adds a new item to a list that has a workflow that does the webservice call to start the Site Workflow.