undefined is not a constructor evaluating new XMLHttpRequest

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Posted on by Xavier Villafuerte

350

Hi, for a project with Dynamics 365 Online version 8.2, I wrote a JS script which runs on the Order Entity, performs a web api query and uses a call to XMLHttpRequest using this pretty straightforward piece of code:

var finalFetchXML = String.Format(query,entityGUID)
var encodedFetchXML = encodeURIComponent(finalFetchXML);
var queryPath = "/api/data/v8.0/salesorderdetails?fetchXml=" + encodedFetchXML;
var requestPath = Xrm.Page.context.getClientUrl() + queryPath;

var req = new XMLHttpRequest();
req.open("GET", requestPath, true);

It works fine in a regular browser but when I use the phone app in iOS (latest version) I found a weird behavior.

If I go the any order record and press the refresh option in the phone app I got the following error:

Event: listLoad

Error: undefined is not a constructor (evaluating new XMLHttpRequest())

If I never press the refresh option in the phone app, the call is made (asynchronously) and a field is updated in the form (after accepting the save prompts).

I would like to understand the reason behind this behavior with the refresh option and as always, any advise from you is much appreciated.

Xavier

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Xavier Villafuerte 350 on at

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RE: undefined is not a constructor evaluating new XMLHttpRequest

Thanks Francesco for your response. It did not work as expected. However I found the solution implementing the call for a new instance of XMLHttpRequest using this code:

function getXHR(){

if(window.XMLHttpRequest){

return new XMLHttpRequest()

}

else try {

return new ActiveXObject('Msxml2.XMLHTTP')

} catch (e) {

try{

return new ActiveXObject("Microsoft.XMLHTTP")

} catch(e) {

return null

}

}

}

Then, I call the getXHR function in my main script as follows:

var req = getXHR()

if (req != null) {

--my code

}

I test it with my original scenario (browser and mobile app) and I have no more errors anymore. As a reference I found the code above in this link:

books.google.com.ec/books;pg=PA151&lpg=PA151&dq=if(XMLHttpRequest)+mobile&source=bl&ots=Va3APYl_5o&sig=S6prjBJarfKrYiUt9nz1iEfd_5o&hl=es&sa=X&ved=0ahUKEwjSnrKthLjYAhVB6SYKHRU3D_UQ6AEIaDAI#v=onepage&q=if(XMLHttpRequest)%20mobile&f=true

I hope it helps

Xavier
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Community Member Microsoft Employee on at

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RE: undefined is not a constructor evaluating new XMLHttpRequest

Hi Xavier,

if seems the client has not still loaded XMLHttpRequest .

Try to incapsuate your call in a setInterval method, like this:

var loadInterval = setInterval(function(){

if(!XMLHttpRequest) return;

clearInterval(loadInterval);

// yourcode
...

}, 3000);

Please let me know if you solve.

If you found the answer helpful, please mark as Verified

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Thank You & Best Regards

Francesco Picchi

Microsoft Dynamics CRM Consultant, Bologna+Milano, ITALY

Independent Contractor

http://www.francescopicchi.com
Xavier Villafuerte 350 on at

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RE: undefined is not a constructor evaluating new XMLHttpRequest

Hi Syed. Well, as far as I understand, the conditional sentence you mention applies only if you want to specify code to be run on an specific type of client, In this case mobile. However, I need to run the web api query in all the Clients and Because of that, I am not using it in my code. Please let me know if I am wrong in any way.
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Syed Ibrahim 6,257 on at

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RE: undefined is not a constructor evaluating new XMLHttpRequest

Hi Xavier,

Did you include the the below check on the js as first step?

if (Xrm.Page.context.client.getClient() == "Mobile")

If not pls add the check and see.

Hope this helps.If the suggestion resolved your query .Pls mark it as answered/verified to close the thread.