Yes, Joffm's solution is very elegant.
Mine is a little more involved but may allow more flexibility in the weightings and could be extended if you want different weighting values for different numbers of selected products.
Insert a multiple-choice question after the products multiple-choice.
We will hide this question, use JavaScript to check one item based on the weighted checked products and then use relevance to show following groups.
Insert the following script into the source of the new multiple-choice and adjust the "weights" values as necessary:
Code:
<script type="text/javascript" charset="utf-8">
$(document).on('ready pjax:scriptcomplete',function(){
// Define the weightings by sub-question code
var weights = {
'SQ001': 50,
'SQ002': 15,
'SQ003': 35
}
// Identify this question
var qID = '{QID}';
var thisQuestion = $('#question'+qID);
var previousQuestion = thisQuestion.prevAll('.multiple-opt:eq(0)');
var prevID = $(previousQuestion).attr('id').replace(/question/, '');
// Hide this question
thisQuestion.hide();
// Listener on the checkboxes
$('input:checkbox', previousQuestion).on('change', function(e) {
// Reset this question
$('.checkbox-item input:hidden', thisQuestion).val('');
$('.checkbox-item input:checkbox', thisQuestion).prop('checked', false).trigger('change');
// Only one item checked
if($('input:checkbox:checked', previousQuestion).length == 1) {
var checkedCode = $('input:checkbox:checked', previousQuestion).attr('id').split('X'+prevID)[1];
var thisItem = $('.question-item[id$="X'+qID+checkedCode+'"]');
$('input:hidden', thisItem).val('Y');
$('input:checkbox', thisItem).prop('checked', true).trigger('change');
}
// Multiple items checked
else if($('input:checkbox:checked', previousQuestion).length > 1) {
// Build a weighted array of the checked items
var sqCodesArr = [];
$('input:checkbox:checked', previousQuestion).each(function(i) {
var checkedCode = $(this).attr('id').split('X'+prevID)[1];
for (i = 0; i < weights[checkedCode]; i++) {
sqCodesArr.push(checkedCode);
}
});
// Randomize the array
shuffleArray(sqCodesArr);
// Check the box corresponding to the first array item
var checkedCode = sqCodesArr[0];
console.log(sqCodesArr);
var thisItem = $('.question-item[id$="X'+qID+checkedCode+'"]');
$('input:hidden', thisItem).val('Y');
$('input:checkbox', thisItem).prop('checked', true).trigger('change');
}
});
});
function shuffleArray(array) {
for (var i = array.length - 1; i > 0; i--) {
var j = Math.floor(Math.random() * (i + 1));
var temp = array[i];
array[i] = array[j];
array[j] = temp;
}
return array;
}
</script>
Sample survey attached:
