Replace String

Replace String

on my page I want to replace

"0" with "a",
"1" with "b",
"2" with "c",
"3" with "d",
"4" with "e",
"5" with "f",
"6" with "g",
"7" with "h",
"8" with "i",
"9" with "j",

for example any where on my website i want to replace
" 3 Watch 12 Taylor Swift's New Videos for Out of the Woods In 2015 !" with:
" d Watch  bc Taylor Swift's New Videos for Out of the Woods In  cabf !"