$("#calculate").click(function(){ var lowerLimits = $('#lowerlimits').val().split(", "); var upperLimits = $('#upperlimits').val().split(", "); var frequencies = $('#frequencies').val().split(", "); var sum = 0; var computation = 0; var size = 0; var mid = 0; for (var i = 0; i < lowerLimits.length; i++) { mid = (parseFloat(lowerLimits[i]) + parseFloat(upperLimits[i])) / 2; sum += mid * parseFloat(frequencies[i]); size += parseFloat(frequencies[i]); } if(lowerLimits && lowerLimits.length > 0 && lowerLimits[0] !== "") { computation = sum / size; } $('#result').text(parseFloat(computation).toFixed(2)); }); $("input").change(function(){ var isInvalid = $('#itemDiv').hasClass('is-invalid') || $('#frequencyDiv').hasClass('is-invalid'); if(isInvalid){ $("#add").prop("disabled", true); }else{ $("#add").removeAttr('disabled'); } }); $("#add").click(function(){ var lowerlimits = $('#lowerlimits'); var upperlimits = $('#upperlimits'); var lowerLimit = $('#lowerlimit').val(); var upperLimit = $('#upperlimit').val(); var listOfLowerLimits = lowerlimits.val(); var listOfUpperLimits = upperlimits.val(); var frequencies = $('#frequencies'); var frequency = $('#frequency').val(); var listOfFrequencies = frequencies.val(); if(lowerLimit && lowerLimit.length > 0 && upperLimit && upperLimit.length > 0 && frequency && frequency.length > 0){ if(listOfLowerLimits && listOfLowerLimits.length > 0){ listOfLowerLimits += ', ' + lowerLimit; listOfUpperLimits += ', ' + upperLimit; listOfFrequencies += ', ' + frequency; }else{ listOfLowerLimits = lowerLimit; listOfUpperLimits = upperLimit; listOfFrequencies = frequency; } $('#itemList').append("" + lowerLimit + '-' + upperLimit + ""); $('#frequencyList').append("" + frequency + ""); } lowerlimits.val(listOfLowerLimits); upperlimits.val(listOfUpperLimits); frequencies.val(listOfFrequencies); });

Enter Item's Range & Frequency and Press Add Button.

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Items
Frequency