Print Duplicate Element in Array

var arraySize = prompt('How many element you want to enter in Array...');
var array = [];
for (var i = 1; i <= arraySize; i++) {
    array.push(prompt(`Enter Element ${i}...`));
}

var duplicateValues = [];

function duplicateRemover(sourceArray) {
    for (var i = 0; i < sourceArray.length; i++) {
        for (var j = i + 1; j < sourceArray.length; j++) {
            if (sourceArray[i] === sourceArray[j]) {
                duplicateValues.push(sourceArray.splice(j, 1));
            }
        }
    }
    return duplicateValues;
}
document.write(`<strong>With Duplicate Values</strong><br>Array : ${array.join(', ')}`);
document.write(`<br><strong>Duplicate Values Removed</strong><br>Array : ${duplicateRemover(array).join(', ')}`);