Huge string replace in JavaScript?

Huge string replace in JavaScript?

I've got a small JavaScript application that will parse files the user
drops into the browser. Recently I've discovered an issue with some
non-english characters. The file types that are dropped on here are using
the Windows-1252 character set, so characters such as ñ, are actually
coming through as ñ and I must convert them all to the proper characters.
I've found an extremely useful website with the collection of the
characters, and their counterparts that I need to convert to.
I've condensed that down into two JavaScript arrays:
var toReplace = ["À", "Ã", "Â", "Ã", "Ä", "Ã…", "Æ", "Ç", "È",
"É", "Ê", "Ã&lsqauo;", "ÃŒ", "Ã", "ÃŽ", "Ã", "Ã", "Ã'", "Ã'", "Ã"", "Ã"", "Õ",
"Ö", "×", "Ø", "Ù", "Ú", "Û", "Ãœ", "Ã", "Þ", "ß", "Ã", "á",
"â", "ã", "ä", "å", "æ", "ç", "è", "é", "ê", "ë", "ì", "í",
"î", "ï", "ð", "ñ", "ò", "ó", "ô", "õ", "ö", "÷", "ø", "ù",
"ú", "û", "ü", "ý", "þ", "ÿ"];
var replaceWith = ["À", "Á", "Â", "Ã", "Ä", "Å", "Æ", "Ç", "È", "É", "Ê",
"Ë", "Ì", "Í", "Î", "Ï", "Ð", "Ñ", "Ò", "Ó", "Ô", "Õ", "Ö", "×", "Ø", "Ù",
"Ú", "Û", "Ü", "Ý", "Þ", "ß", "à", "á", "â", "ã", "ä", "å", "æ", "ç", "è",
"é", "ê", "ë", "ì", "í", "î", "ï", "ð", "ñ", "ò", "ó", "ô", "õ", "ö", "÷",
"ø", "ù", "ú", "û", "ü", "ý", "þ", "ÿ"];
What would be the most efficient way to replace all characters from a
paragraph in toReplace with it's counterpart (same index) in replaceWith?
I'm hoping this won't be too loop-heavy since it's not uncommon to drop
over 100 files into this application that already does some heavy looping
& parsing.
Perhaps there is a better way to do this instead of keeping these
characters in arrays?