Solved
Generate random values using Javascript
I am using the below javascript to define an array and retrieve random elements from the array.
var COST = ["$400","$500","$600","$700","$800"];
var COST_a1 = COST[Math.floor(Math.random()*COST.length)];
alert (COST_a1) ; /* for debugging */
When I preview the survey, Qualtrics runs this piece of code TWICE. The alert box pops up twice with different values for COST_a1.
This is causing issues on another page when I try to capture the value of Cost_a1
using
this.setChoiceValue(3,COST_a1);
I only need the random value to be generated once. Any guidance on this matter is appreciated.
Thank you.
Best answer by Michael_Campbell_RedPepper
For sure! You can store it as an Embedded Data Field using this Javascript:
`Qualtrics.SurveyEngine.setEmbeddedData('FIELD', value);`
`Qualtrics.SurveyEngine.getEmbeddedData('FIELD');`
(I included the code for retrieving EDF's, too, just for kicks)
+3Is this in the Preview Mode? The code runs for both the Mobile and Desktop versions of the code, independently.
+3Ah! Well, that is to be expected in this scenario. It's frustrating, but part of the system's functionality. One less intrusive way of debugging is using `console.log()` to display things in the Developer Console of your browser.
Thank you for the info. Is there any way for me to capture the values that were 'randomly' picked out from the array ? I am needing these values for data analysis later.
+3For sure! You can store it as an Embedded Data Field using this Javascript:
`Qualtrics.SurveyEngine.setEmbeddedData('FIELD', value);`
`Qualtrics.SurveyEngine.getEmbeddedData('FIELD');`
(I included the code for retrieving EDF's, too, just for kicks)
+3That will show up in your Reporting Services.
Thank you Michael for the quick responses. I will give it a shot.
Out of curiosity, does the code execute twice only in Preview mode or even when I publish the survey.
+3Of course! And it should only execute it once. One thing I strongly recommend is keeping the code inside the Lifecycle methods of the Qualtrics Survey (i.e. `Qualtrics.SurveyEngine.addOnload()`) this will ensure that things run at the right time and only once.
Use the `AddOnLoad()` for calculating, populating, and storing data that is needed to be done _before_ display, and then use `Qualtrics.SurveyEngine.addOnReady()` for reading data for display. It's a complicated topic, but those two pointers will get you 90% of the way there!
Do you mean add the following within addOnReady()
Qualtrics.SurveyEngine.setEmbeddedData('FIELD', value);
Qualtrics.SurveyEngine.getEmbeddedData('FIELD');
and how do I eventually get these values into the output. (Data & Analysis -> Export)
+3Yeah! That is the best place to put it.
And Embedded Data Fields show up in your reporting :)
+3I'm glad to hear it!! Congrats!
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