JavaScript RegExp Not Targeting all Instances of String

Question

My regular expression won't return all instances of <li>.+<\/li> found in textarea.

I Googled, and tried /g, but doesn't work.

Here is the Fiddle.

This is my function(){...}:

function doIt() {

    var input = document.getElementById("input");
    var olPatt = /<ol>\s*(?:<li>.+<\/li>\s*)+<\/ol>/,
        ol = input.value.match(olPatt),
        olLi = ol.toString().match(/<li>/g), // MATCH ALL <li> with /g
        olLiB = ol.toString().match(/<\/li>/g); // MATCH ALL </li> with /g
    var i = 1; // start with 1

    input.value = input.value.replace(/<ol>/, "").replace(/<\/ol>/, "").replace(/\s*/, ""); // remove ol tags

    input.value = input.value.replace(olLi, function() {return i++ + "." + " ";}).replace(olLiB, " ");
    // should replace ALL <li> found in <ol> with number starting with 1 </li>        

}

If you're given this:

<ol>
<li>Hello world! :)</li> 
<li>Hello how are you</li> 
<li>good</li>
</ol>

It returns this: (incorrect)

1. Hello world! :)  
<li>Hello how are you</li> 
<li>good</li>

But, I want this: (correct)

1. Hello world! :)  
2. Hello how are you
3. good

I believe you just need to add 'g' to the end for a global search. So like this: input.value.replace(/<ol>/g, "") — Zack Argyle
– Zack Argyle, Commented Jun 26, 2014 at 23:11
Also, {1} is redundant, and you should consider using an HTML parser (like the one that’s built into browsers). — Ry-
– Ry- ♦, Commented Jun 26, 2014 at 23:12
@Matthew: I would definitely recommend against it; it’s misleading, because the {1} only applies to the >. If you changed it to 2 later, it would match <ol>>, not <ol><ol>. — Ry-
– Ry- ♦, Commented Jun 26, 2014 at 23:17

sahbeewah · Accepted Answer · 2014-06-26 23:22:16Z

1

http://jsfiddle.net/3jthN/10/

You need to add the global modifier at the point where you do the actual replacing.

In this case it's in this line:

input.value = input.value.replace(olLi, function() {return i++ + "." + " ";}).replace(olLiB, " ");

Because you're specifying the regex pattern from a variable, you need to use the RegExp constructor and pass the global modifier as the second argument. The fiddle demonstrates this.

new RegExp(olLi, 'g')

answered Jun 26, 2014 at 23:22

sahbeewah

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Comments

Ry- · Accepted Answer · 2014-06-26 23:24:09Z

1

Here:

input.value = input.value.replace(olLi, function () {
    return i++ + "." + " ";
}).replace(olLiB, " ");

olLi and olLiB are already matches on ol.toString(). Just keep them as regular expressions, or perform the replacement in another callback (this seems the most correct):

input.value = input.value.replace(/<ol>\s*((?:<li>.+<\/li>\s*)+)<\/ol>/g,
    function (list, listItems) {
        return listItems.replace(/<li>/g, function () {
            return i++ + '. ';
        }).replace(/<\/li>/g, '');
    });

Updated jsFiddle

answered Jun 26, 2014 at 23:24

Ry-♦

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2 Comments

Matthew Over a year ago

Thank you, this works great! I have a question; where is the list parameter? Is it just there as a placeholder? The first parameter in function (list, listItems) {...}

Ry- Over a year ago

@Matthew: Yep! It contains the entire match; listItems is the parenthesized subexpression, i.e. the same thing but minus the <ol> and </ol>.

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