To trigger a workflow using JavaScript, you can follow these steps:
First, obtain the workflowId by specifying its name and type definition.
var entityId = // Insert Entity GUID here
var workflowId = // Insert Workflow GUID here
var url = // Your organization's root URL
var orgServicePath = "/XRMServices/2011/Organization.svc/web";
url = url + orgServicePath;
var request;
request = "<s:Envelope xmlns:s=\"http://schemas.xmlsoap.org/soap/envelope/\">" +
"<s:Body>" +
"<Execute xmlns=\"http://schemas.microsoft.com/xrm/2011/Contracts/Services\" xmlns:i=\"http://www.w3.org/2001/XMLSchema-instance\">" +
"<request i:type=\"b:ExecuteWorkflowRequest\" xmlns:a=\"http://schemas.microsoft.com/xrm/2011/Contracts\" xmlns:b=\"http://schemas.microsoft.com/crm/2011/Contracts\">" +
"<a:Parameters xmlns:c=\"http://schemas.datacontract.org/2004/07/System.Collections.Generic\">" +
"<a:KeyValuePairOfstringanyType>" +
"<c:key>EntityId</c:key>" +
"<c:value i:type=\"d:guid\" xmlns:d=\"http://schemas.microsoft.com/2003/10/Serialization/\">" + entityId + "</c:value>" +
"</a:KeyValuePairOfstringanyType>" +
"<a:KeyValuePairOfstringanyType>" +
"<c:key>WorkflowId</c:key>" +
"<c:value i:type=\"d:guid\" xmlns:d=\"http://schemas.microsoft.com/2003/10/Serialization/\">" + workflowId + "</c:value>" +
"</a:KeyValuePairOfstringanyType>" +
"</a:Parameters>" +
"<a:RequestId i:nil=\"true\" />" +
"<a:RequestName>ExecuteWorkflow</a:RequestName>" +
"</request>" +
"</Execute>" +
"</s:Body>" +
"</s:Envelope>";
var req = new XMLHttpRequest();
req.open("POST", url, false);
// Return responses in XML format, as JSON is not supported.
req.setRequestHeader("Accept", "application/xml, text/xml, */*");
req.setRequestHeader("Content-Type", "text/xml; charset=utf-8");
req.setRequestHeader("SOAPAction", "http://schemas.microsoft.com/xrm/2011/Contracts/Services/IOrganizationService/Execute");
req.send(request);
If the request returns status 200, it means the request was successful. This code was tested on a CRM2011 environment.
It is advisable to create a WCF rest or web API, referencing the IOrganizationService, and utilizing CRM service operations through an intermediate WCF rather than directly accessing IOrganizationService.