How can I escape a single quote?

As you’re in the context of HTML, you need to use HTML to represent that character. And for HTML you need to use a numeric character reference ' (' hexadecimal):

<input type='text' id='abc' value='hel&#39;lo'>

You can use ' (which is iffy in IE) or ' (which should work everywhere). For a comprehensive list, see the W3C HTML5 Named Character References or the HTML entities table on WebPlatform.org.

You could use HTML entities:

• ' for '
• " for "
• ...

For more, you can take a look at Character entity references in HTML.