How do I convert multi-line text column to multiple entries in new list

Question

I have a multiline text column with many 9 digit numbers delimitated by commas that i would like to extract so I can check for duplicates. If I can check for duplicates without extracting that would be even more helpful.

Answer 1

//get Values of multiline field in variable
var text=SPUtility.GetSPField('Description').GetValue();
//Multiline textbox has html elements, trimming them
text=text.replace("<p>","").replace("</p>","").replace("<br>","");
//converting each comma separated 9 digit number into array
var array=text.split(',');
array=array.sort();
//function to check duplicates in array. True if elements of array is unique else false
function checkIfArrayIsUnique(myArray)
{
for (var i = 0; i < myArray.length; i++)
{
if(myArray.indexOf(myArray[i]) !== myArray.lastIndexOf(myArray[i]))
{
return true;} 
} 
return false;   // this means not unique
}
//flag will be false if non unique numbers in multiline textbox
var flag=checkIfArrayIsUnique(array);