Using Javascript to get slider value and save to embedded data

Hi everyone,
I'm using a slider question to record a participant's willingness to pay for a certain product as part of an economics experiment. This WTP value will be compared to a randomly generated value in the survey flow. Unfortunately I've not been able to extract the value from the slider and set it to an embedded data field.
My JS so far on the slider question is:

Qualtrics.SurveyEngine.addOnload(function()
{
/*Place your JavaScript here to run when the page loads*/
var randomNum = (Math.random() * (0.21 - 0.0) + 0.0).toFixed(2);
Qualtrics.SurveyEngine.setEmbeddedData("WTP_Random", randomNum);
console.log(randomNum);
});
Qualtrics.SurveyEngine.addOnReady(function()
{
var value;
var that = this.questionId;
jQuery(document).on('change',function(){
value=parseInt(jQuery("[id='"+that+"~1~result']").val());
});
console.log(value);
Qualtrics.SurveyEngine.setEmbeddedData("WTP_Subject", value);
});
Qualtrics.SurveyEngine.addOnUnload(function()
{
/*Place your JavaScript here to run when the page is unloaded*/
});

Any help would be greatly appreciated.
Thanks, Chris