jQuery selector value escaping

Question

I have a dropdown list that contains a series of options:

<select id=SomeDropdown>
  <option value="a'b]&lt;p>">a'b]&lt;p></option>
  <option value="easy">easy</option>
<select>

Notice that the option value/text contains some nasty stuff:

• single quotes
• closing square bracket
• escaped html

I need to remove the a'b]<p> option but I'm having no luck writing the selector. Neither:

$("#SomeDropdown >option[value='a''b]<p>']");

or

$("#SomeDropdown >option[value='a\'b]<p>']");

are returning the option.

What is the correct way to escape values when using the "value=" selector?

Answer 1

I use this function to escape jquery selectors. It escapes basically everything questionable but may be too aggressive.

function escapeStr(str) 
{
    if (str)
        return str.replace(/([ #;?%&,.+*~\':"!^$[\]()=>|\/@])/g,'\\$1');      

    return str;
}

Answer 2

I don't think you can. It should be:

#SomeDropdown >option[value='a\'b]<p>']

And this does work as a CSS selector (in modern browsers). Expressed in a JavaScript string literal you would naturally need another round of escaping:

$("#SomeDropdown >option[value='a\\'b]<p>']")

But this doesn't work in jQuery because its selector parser is not completely standards-compliant. It uses this regex to parse the value part of an [attr=value] condition:

(['"]*)(.*?)\3|)\s*\]

\3 being the group containing the opening quotes, which weirdly are allowed to be multiple opening quotes, or no opening quotes at all. The .*? then can parse any character, including quotes until it hits the first ‘]’ character, ending the match. There is no provision for backslash-escaping CSS special characters, so you can't match an arbitrary string value in jQuery.

(Once again, regex parsers lose.)

But the good news is you don't have to rely on jQuery selectors; there are perfectly good DOM methods you can use, in particular HTMLSelectElement.options:

var select= document.getElementById('SomeDropdown');
for (var i= select.options.length; i-->0;) {
    if (select.options[i].value=="a'b]<p>") {
        // do something with option
}   }

This is many times simpler and faster than asking jQuery to laboriously parse and implement your selector, and you can use any value string you like without having to worry about escaping special characters.

Answer 3

use .filter() with a custom function. txt should contain your nasty string, or you could just replace indexOf with any other function you choose.

$("#SomeDropdown option")
   .filter(function(i){
       return $(this).attr("value").indexOf(txt) != -1;
   })
   .remove();

Answer 4

I find that you can use \ \ to escape selectors. Think of it as one \ for the regex and one to escape from the regex.

Example:

$(this).find('input[name=user\\[1\\]\\[name\\]]').val();