Shrink DIV to text that’s wrapped to its max-width?

It’s not the prettiest solution but it should do the trick. The logic is to count the length of each word and use that to work out what the longest line is that will fit before being forced to wrap; then apply that width to the div. Fiddle here: http://jsfiddle.net/uS6cf/50/

Sample html…

<div class="wrapper">
    <div class="shrunken">testing testing</div>
</div>

<div class="wrapper">
    <div class="shrunken fixed">testing testing</div>
</div>

<div class="wrapper">
    <div class="shrunken">testing</div>
</div>

<div class="wrapper">
    <div class="shrunken fixed">testing</div>
</div>

<div class="wrapper">
    <div class="shrunken" >testing 123 testing </div>
</div>

<div class="wrapper">
    <div class="shrunken fixed" >testing 123 testing </div>
</div>

And the javacript (relying on jQuery)

$.fn.fixWidth = function () {
    $(this).each(function () {
        var el = $(this);
        // This function gets the length of some text
        // by adding a span to the container then getting it's length.
        var getLength = function (txt) {
            var span = new $("<span />");
            if (txt == ' ')
                span.html('&nbsp;');
            else
                span.text(txt);
            el.append(span);
            var len = span.width();
            span.remove();
            return len;
        };
        var words = el.text().split(' ');
        var lengthOfSpace = getLength(' ');
        var lengthOfLine = 0;
        var maxElementWidth = el.width();
        var maxLineLengthSoFar = 0;
        for (var i = 0; i < words.length; i++) {
            // Duplicate spaces will create empty entries.
            if (words[i] == '')
                continue;
            // Get the length of the current word
            var curWord = getLength(words[i]);
            // Determine if adding this word to the current line will make it break
            if ((lengthOfLine + (i == 0 ? 0 : lengthOfSpace) + curWord) > maxElementWidth) {
                // If it will, see if the line we've built is the longest so far
                if (lengthOfLine > maxLineLengthSoFar) {
                    maxLineLengthSoFar = lengthOfLine;
                    lengthOfLine = 0;
                }
            }
            else // No break yet, keep building the line
                lengthOfLine += (i == 0 ? 0 : lengthOfSpace) + curWord;
        }
        // If there are no line breaks maxLineLengthSoFar will be 0 still. 
        // In this case we don't actually need to set the width as the container 
        // will already be as small as possible.
        if (maxLineLengthSoFar != 0)
            el.css({ width: maxLineLengthSoFar + "px" });
    });
};

$(function () {
    $(".fixed").fixWidth();
});