I have no idea what your code is trying to do overall, but you can fix this function that removes commas:
function checkNumeric(objName) {
var lstLetters = objName;
var lstReplace = lstLetters.replace(/\,/g,'');
}
by changing it to this:
function removeCommas(str) {
return(str.replace(/,/g,''));
}
You weren't returning the changed string from the function and I changed the name of the function and parameters to represent what it does.
str.replace returns the changed string. It does not change the string you started with so in order to do something with the result of the replacement, you have to either return that from the function or assign it to some other string. As you had it, nothing was happening with the replaced string so the function did nothing.