first time I believe I have posted in stackoverflow and I hope I can explain what I would like to try and accomplish.
To try and phrase my question the most concisely, is there a way I can have a user input a string of words into a form in HTML, then use Javascript to check to see if any of those words match a variable that is already declared and then reference that variable so that I can use the value that is saved there?
For example we will have var feet = 12 declared, and a user inputs the word "feet" into a text field. I want to be able to take the user input and use it to reference the variable for later purposes in the code.
Hopefully explains my scenario well enough and someone can offer some advice
Thanks!
If the variable is a global variable, you can use window[varname] to get the value of the variable whose name is in varname.
Do you really need to allow the user to access any random Javascript variable? If not, a better approach would be to use an object to hold the data you want to allow the user to access. E.g.
var units = {
feet: 12,
inches: 1,
...
}
var conversion_factor = units[user_input];
Related
Hey everyone, i need help with something.
I've divided the picture into sections so it's easier to look at.
This is really bugging me and i don't know if i can solve it this way.
Thanks to anyone that can help me... Here i go:
So in section 1 i've created a basic input with a name property, actually i've made 4 of them but this one is the example (the name property is important)
In section 2 , those are the inputs on the page and i need to change the variable depending if the inputs is checked or not
The variable in JS file is called requireInteraction and it's set to false
So im doing a forEach on those 4 inputs (each one has a name property that matches the variable name in JS) and i want to change the variable in JS if the checkbox with that name is Checked. I tried using Computed Properties.
So when silent is checked (with the silent name property) i want the variable "silent" in JS to switch to true.
How can i extract the input name (which has the same name of the JS variable) and make it so it's like i actually typed "silent = true" and changed the JS variable.
I don't really know why you can't use
requireInteraction = true;
but here, in case that you have some reason you can't just use the variable directly, you could use an object to serve as a target to index into:
const context = {
requireInteraction: false,
};
Then later on, you can use something similar to your original code:
context[el.name] = true;
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.
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}
I am trying to make a graph of a simple function y=k*x+b.
A user enters a function into the input field, for example:
1/3*x+3
and when he/she clicks the submit button, a JavaScript function is supposed to take this input value as an actual calculation sequence and assign a variable to it (I only need to get certain y values here, so the x variable has its limits):
for (x=1;x<=40;x++)
{
result = window.document.menu.inputFunction.value;
}
The above code doesn't work. No wonder why - I am just a beginner at this. However, is this really harder than it looks, or am I missing out something? I considered trying regular expressions for this at one point, but my head hurts by even thinking about using them.
Any ideas?
You could eval it:
result = eval(window.document.menu.inputFunction.value);
There are obviously some limitations to this approach:
The user must enter a valid javascript expression
The user must use x as variable name because that's what you are using in the loop
The code is vulnerable because the user can enter and execute any javascript expression he likes
For a more robust solution you might consider using a javascript mathematical expression evaluator.
This is my first post.
I'm trying to do some basic meta-programming with javascript, and I was wondering if there is a way of get the id of a particular object and with that id, access to the variable name, or get simply the variable name of a particular object. I wanna recreate a situation in which you first create every single html in a web page, and append to some of the html tags events associated to a particular class -example class Person-. for example: Supposed the next code:
var someFunction = function(someText){alert(someText);}
function SomeClassFunction(){
this.aClassFunction = someFunction;
}
var aVariableName = new SomeClassFunction();
and in the HTML code suppose I have the next piece of code.
<html>
<head>
<title></title>
</head>
<body>
<div onclick="aVariableName.aClassFunction('Some text to show in alert');">
</div>
</body>
</html>
Then, as you may notice the onclick event uses the aVariableName I created before, but because I first create the name of the variable and then append the name in the code cause I knew aVariableName was the name of that object. What I wanna do or implement is to create the text above in html without know the variable name of an specific object. I have surfed on the net but, unfortunately I haven't found anything about it.
i dont know how to get the name of a variable from the code its self without doing a whole load of work parsing stuff, which will get messy, and i'd shoot someone for this.
var someValue;
var foo = function() { someValue; }
alert((foo + '')); // this is now a string, use substr to extract variable name
You know you can set events like this in javascript someElement.onclick = someFunction so you dont really need to know the name of the variable if all you're doing is setting an event handler.
In general, no — you can't get the name of a particular variable or its "id" either.
If you really want to, it may be possible to do Bad Things with exceptions and stack traces to get that information… But I don't know off the top of my head how to do that.
Edit: I assume that, by “variable ID”, you mean “a unique identifier for the object referenced by that variable”, like Python's id builtin:
>>> x = {}
>>> y = z = {}
>>> (id(x), id(y), id(z))
(123, 567, 567)
I'm not 100% sure that I understand your question correctly in regards to meta-programming, but typically you would attach an event handler to the click event of the DOM element, then you can examine properties of the element within the handler.
There are a couple things in JavaScript that facilitate meta-programming: eval will let you interpret arbitrary code, so you can build a string of code and eval it. The security concerns are numerous. You can also access properties of an object by index or by name, e.g.
aVariableName.aClassFunction
is the same as
aVariableName["aClassFunction"]
Hope that helps.