Remove Jargon but keep real characters

I"m getting bombarded by spam with posts like below, so what would be the best and most efficient way of remove all the jargon from something like this:

<texarea id="comment">ȑ̉̽ͧ̔͆ͦ̊͛̿͗҉̷̢̧̫̗̗͎͈͕e̷̪͓̼̼̣̻̻͙͔̳̘̗͙̬̱͎ͭ̃͗ͩͯͥͬ̂ͧ开发者_如何转开发͐͌̑̅͢͜ͅd̴̦̺̖̣͎̲̥͕̗̺̯̤͗ͬ͌ͧ̓͒ͭ́̋ͩͥ͊̇̓̌ͫ̃́́͠</textarea>

I'm assuming RegEx, but what exactly are those things called and how would it be referenced in RegExp? The problem lays within a <textarea> tag, and upon retrieving the value, I'd like to be able to remove all that jargon from the value and have it only display the real characters which in this case should be red.

Allowing other Unicode type of characters are essential, but not characters that stack on top of each other.

Zalgo waits behind the wall.

You want to filter out combining characters, such as the diacritical marks listed here.

You should be able to get away with a simple character class pattern match, i.e.:

fooString.replace(/[\u0300-\u036f\u0483-\u0489\u1dc0-\u1dff\u20d0-\u20ff\ufe20-\ufe2f]/, "");

If you want to limit content to one combination per character (not that this really alleviates all negative side-effects), you could simply use

fooString.replace(/([\u0300-\u036f\u0483-\u0489\u1dc0-\u1dff\u20d0-\u20ff\ufe20-\ufe2f])[\u0300-\u036f\u0483-\u0489\u1dc0-\u1dff\u20d0-\u20ff\ufe20-\ufe2f]*/, "$1");

EDIT: Added a number of other combining character ranges. This is most likely still not exhaustive.

Removing combining diacriticals will make input of some languages (such as Vietnamese) difficult or impossible, so you should reconsider.