Replacing '<' & '>' with javascript

Question

I am trying to append a parsed email to a textarea with javascript, and this is proving to be particularly difficult because of the < & > in email addresses like <[email protected]>

Here is an example of my situation in action. https://jsfiddle.net/xxchz97L/

So I am trying to do a str.replace on the < & > but nothing I do seems to work. Does anyone know how to do this?

Here is a simple excerpt of my code. I am also including jQuery.

HTML

<textarea class="form-control template_data" id="content" name="content" rows="8" cols="80"></textarea>

Javascript

var my_text = "From: Foo Bar <[email protected]> Date: Sat, Apr 8, 2017 at 2:29 PM";
var regEx = '/<|>/g';
my_text.replace(regEx, "*");
my_text = my_text.replace("&lt;", "*");
my_text = my_text.replace("&gt;", "*");
$('#content').append(my_text);
alert(my_text);

PS

I figured there would be no way to append < | > into a textarea as html would think I was posting HTML. If there is someone that does know how to do this please let me know.

if i use following in your fiddle, it works: my_text = my_text.replace("<", "*"); my_text = my_text.replace(">", "*"); Use < > instead of codes — tech2017
– tech2017, Commented May 8, 2017 at 18:54
You can include those characters in the <textarea> if you turn them into HTML entities (convert < to < and so on). You don't have to turn them all into asterisks. — Pointy
– Pointy, Commented May 8, 2017 at 19:22

Pr3ds · Accepted Answer · 2017-05-08 19:11:08Z

2

Use the RegExp, is very easy :)

var regEx = new RegExp("[<>]","g");

for replace use:

yourString = yourString.replace(regEx, "yourReplace");

Do not forget the immutability of the string

edited May 8, 2017 at 19:11

answered May 8, 2017 at 19:00

Pr3ds

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5 Comments

Thomas Valadez Over a year ago

So you cleared all the line breaks then ran it. That seems like a pretty clean solution.

Pr3ds Over a year ago

Not only that, but had a detail in the first replace, which was not reassigning to the String. You will not even need the other two "replace"

Pointy Over a year ago

@ThomasValadez why do you want to change the characters to "*"? Why not just HTML-escape them?

Thomas Valadez Over a year ago

@Pointy I was experimenting with a few things, I figured that would be the easiest option. Are you talking about something like this stackoverflow.com/questions/6234773/…

Pointy Over a year ago

I'm talking about something like my answer :)

Pointy · Accepted Answer · 2017-05-08 19:24:24Z

2

A general HTML sanitizer function really only needs one .replace() call:

var sanitize = function() {
  var map = { "<": "&lt;", ">": "&gt;", "&": "&amp;" },
      rx = /[<&>]/g;

  return function(text) {
    return text.replace(rx, function(match) {
      return map[match];
    };
  };
}();

The .replace() callback takes each matched special character and uses it as a key to lookup the replacement in a map.

With this, you can preserve the actual content for the <textarea> if you use the function on the contents when the page is prepared.

Note that you don't have to worry about this when setting the .value property of the <textarea> with JavaScript.

edited May 8, 2017 at 19:24

answered May 8, 2017 at 19:05

Pointy

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3 Comments

Alexander Solonik Over a year ago

sorry to be asking a dumb question , but on what does this function get called on and who is passing text into the first inner function ?

Pointy Over a year ago

@AlexanderSolonik The function to call is sanitize(). If you were to call sanitize("<b>Hello World</b>") the return value would be the string "<b>Hello World</b>"

Alexander Solonik Over a year ago

perfect ! got it :)

Scott Marcus · Accepted Answer · 2017-05-08 18:55:34Z

0

You are trying to replace the escaped characters when no such characters exist in the string.

Change:

my_text = my_text.replace("&lt;", "*");
my_text = my_text.replace("&gt;", "*");

to:

my_text = my_text.replace("<", "*");
my_text = my_text.replace(">", "*");

answered May 8, 2017 at 18:55

Scott Marcus

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1 Comment

Thomas Valadez Over a year ago

Awesome that worked for the first line. Now I have two questions. Why doesn't the regex expression take care of that? and how would I make it span multiple lines of text?

dinimer · Accepted Answer · 2017-05-08 19:03:34Z

0

Your Problem seems to be an incorrect RegEx. Try the following:

my_text = my_text.replace(/(\<|\>)/g, '');

edited May 8, 2017 at 19:03

answered May 8, 2017 at 18:58

dinimer

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