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Asked: 2026-05-31T03:30:58+00:00

This is the source of my simple HTML page (save as .html file): <!DOCTYPE

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This is the source of my simple HTML page (save as .html file):

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<script type="text/javascript">
function convert(){
 var ele1 = document.getElementById("somewhere");
 var replaced;
 replaced = ele1.value;
 replaced = replaced.replace(/&/ig, "&amp;");
 replaced = replaced.replace(/</ig, "&lt;");
 replaced = replaced.replace(/>/ig, "&gt;");
 replaced = replaced.replace(/'/ig, "&#039;");
 replaced = replaced.replace(/"/ig, "&quot;");
 ele1.value = replaced;
}
</script>
</head>

<body>
<textarea cols="70" id="somewhere" rows="15" style="background: none repeat scroll 0% 0% rgb(250, 250, 250); border: 2px solid rgb(204, 204, 204);"></textarea><br />
<input onclick="convert();" type="button" value="Encode" />
</body>
</html>

What this page does is, any code put in the textarea is HTML-encoded/escaped when the “Encode” button is clicked — essentially all instances of &, <, >, ' and " in the input code are replaced with their respective HTML entities.

How do I modify the JavaScript code in the page, so that only the input code between <pre> and </pre> tags is modified as aforementioned?

EDIT: As I see it I wasn’t clear. First you need to save the HTML code I gave above into a .html file and open it in a browser. Then you will see a textarea/textbox with an “Encode” button below it.

Any code put into the text area is escaped when the “Encode” button is pressed.

I want to modify the JavaScript code in the HTML code above, so that (for instance) if I put the following code in the textbox:

It's mine.
<pre>
<input onclick="convert();" type="button" value="Encode" />
</pre>
It's also mine.

and hit the “Encode” button, only the code between <pre> tags is escaped. I hope I am clear this time.

Hope I am clear, and can get some help. Thanks.

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1 Answer

  1. Editorial Team

    Insead of using:

    var ele1 = document.getElementById("somewhere");

    You could use:

    var ele1 = document.getElementsByTagName("pre");

    However this might return multiple elements since there could be multiple <pre> sections in your html.

    But again, if your goal is to produce a safe output, escaping is not a preferred solution. Have a look at Markdown for example:
    http://daringfireball.net/projects/markdown/basics

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