How do I use javascript (jquery) to set the value of a text box?

Here's my problem. I have a survey where I prefill the textbox with embedded data calculated from a previous set of questions. That works wonderfully. But, when the user goes back to do the survey again, the calculations are not being populated because the form is prefilled with their prior answers.

In order to get around this, I'd like to set the textbox value using javascript rather than embedded data. Something like document.getElementByID("Question").value = "ThisValue";

To complicate things, the textbox is actually inside a side by side question. The actual question ID is ${q://QID22/ChoiceTextEntryValue/3/2} and I can't figure out how to do this. Any help is appreciated! I'm certain it's simpler than I know.

For what it's worth, I've tried this to no avail: document.getElementById("QR~QID22#3~2").value = "My value";