Develop Reference

GTM - Truncated DataLayer Variable into Custom Javascript Variable

I currently have a dlv variable to store "First Name" (gtm.element.2.value) which is working correctly.
I also a dlv to store "D.O.B." which is also working correctly - gtm.element.5.value (this is formatted MM/DD/YYYY).
However, I'd like to only show the first initial in the First Name dlv and the Year in the DOB dlv. I'm thinking of utilizing a Custom JS variable but am open to ideas if there is an easier route.
Can anyone help provide what that Custom JS variable would look like? I've been searching for some examples but not having luck with this specific example.
Appreciate the help in advance!

To get the first initial (i.e. first character) of the First Name variable, you can indeed use a Custom JavaScript variable with this:
function() {
return {{first_name}}[0]; // Replace with the actual DLV reference
}
Similarly, to get just the year (YYYY) of the D.O.B., you can use a Custom JS variable:
function() {
return {{date_of_birth}}.split('/').pop(); // Replace with the actual DLV reference
}
Obviously you might want to add some checks to make sure the input is in a predictable format. For example, you might want to check that {{first_name}} is a string of non-zero length, and you might want to check that {{date_of_birth}} actually contains a date string with slash as the separator.

Pass Component Name as Argument and then attach method (not working?)

Maybe I'm not using the right terms/names for my searches but I have not been able to find anything on this topic. I would have thought this would be an easy thing to find. What I'm doing is passing a component name to a function and then trying to use the component's name by attaching a method to it. I have confirmed (via Dev Tools) that the name is correctly being passed but when I use the variable and attach the method the specific request does not work. If I 'hard-code' the exact component name to the method it works perfectly. This makes me think the (various) ways I've been trying to attach the method to the variable name is incorrect (see various attempts below). Can you offer some direction here? Thank you.
Passing to Function ...
const grid_name = "grid_GroupA";
console.log(grid_name); // Shows grid_GroupA
msg_max(newItem, grid_name);
Function (only listing relevant parts)
function msg_max(newItem, grid_target) {
console.log(grid_target); // Shows grid_GroupA
// grid_GroupA.data.add(newItem); // This works ...
// grid_target.data.add(newItem); // This does not work
// (grid_target).data.add(newItem); // This does not work
// [grid_target].data.add(newItem); // This does not work
// grid_target + '.data.add(newItem)'; // This does not work
Thank you ...
Edit ...
In my attempt to provide detail I hope I haven't confused the issue.
In essence, my question is if I can type this exact string
grid_GroupA.data.add(newItem);
and it works for my function, how can I place a variable with the exact string "grid_GroupA" in front of ".data.add(newItem);" and have it seen the same as the line of code that works? Maybe my lack of knowledge here is getting in the way but isn't the line of code that works just a string that is then used to 'find' the object? So, if that assumption is correct, how do I create that same string with the variable? If my assumption is wrong I am a willing learner so I will be all ears. Thank you.

I do not see how grid_target is an object. You are passing grid_name(which is a string) to the function, so grid_target will have no data property, because string doesn't have such a member.
P.S. snake_case is bad option for JavaScript, consider using cameCase instead

How to store variable and set the variable in field

I'm using Selenium 3.17.0.
I want to type a text from a javascript, but it doesn't work!
I have tried this (this types the text "undefined")
and this (this types the entire script as text)
but nothing works! maybe I'm doing wrong the javascript but I don't know, I'm new in all of this, please help!
btw this is my first post, sorry if I'm doing it wrong.

If I understand your question correctly, you are trying to generate a random string using javascript and then store the value in a variable. Then enter that variable value using type.
you have to use execute script command to run the javascript and target (your javascript) should be return "free text" + Math.floor(Math.random()*100) as shown in the below screenshot.

How to get value of Qualtrics Drag & Drop Choice using Javascript

I have what should be a simple answer. I have a drag and drop style multiple choice question on Qualtrics. I have recoded the answers as I wish. I think it assigns to each answer a variable like QID15_1 QID15_2 QID15_3, etc. The outputted data then gives the rank order of that selected option.
So if I ranked them, for example
QID15_3
QID15_1
QID15_2
The value of QID15_3 =1, the value of QID15_1=2, and the value of QID15_2=3.
What is the correct syntax to access these values? I want to set an Embedded Data item with the value of QID15_1, for example (so it should equal 2), but I can't seem to get it correct.
I've tried Qualtrics.SurveyEngine.getSelectedAnswerValue and things like this.
Any help would be appreciated. Thanks!
EDIT: With the help of a friend who knows Java, we figured it out. You can write something like
Qualtrics.SurveyEngine.addOnUnload(function()
{var order=document.getElementById( 'QR~QID15~1' ).getElementsByClassName( 'rank' )[0].innerText;
}

You don't need to set an embedded variable in JavaScript. You can just pipe the value wherever you need it (in a subsequent question, in the survey flow, etc.). It would be:
${q://QIDx/ChoiceNumericEntryValue/y}
where x is the question id and y is the choice id.
EDIT:
You can assign it to an embedded data variable in the survey flow like this:
edvar = ${q://QIDx/ChoiceNumericEntryValue/y}

Javascript json, check all keys for undefined ('null') and set default

Firstoff I'd like to add I've been learning javascript for like only 2 days now. I'm pretty much way ahead of myself with what I'm trying to get but here goes.
I have a json array from which I get data to replace/insert in my page. The first problem I have is that if it comes across an empty ('null') key it will just stop. Will not even try to continu.
document.getElementById("id1")src=json.img1.link;
document.getElementById("id2")src=json.img2.link;
document.getElementById("id3")src=json.img3.link;
json.img2.link is empty ('null' response from json.). javascript will then not replace "id2" but it also won't replace "id3".
I'm now trying to find a solution where it will if nothing else at least set a default.

The script is not continuing executing because it comes to an error --trying to access property link of an undefined object
Try
document.getElementById('id2').src = json.img2 ? json.img2.link : 'defaultLink';
This way your are checking for undefined (ie null) object in img2 and assigning the default value. This assumes that what is not defined (null) is the img2 object.

Actually I don't think your code should work at all, you are missing the. before the src So, try
document.getElementById("id1").src=json.img1.link;
document.getElementById("id2").src=json.img2.link;
document.getElementById("id3").src=json.img3.link;
and let us know if that doesn't solve the problem.
Btw, +points for learning JavaScript and not just straight into jQuery!