This is somewhat of a hack, but will do what you want.

<div id=hidden-resizer style=visibility: hidden></div>

Place this at the bottom of your page, where it will not be moving other elements on the page.

Then do this:

var size;

var desired_width = 50;

var resizer = $(#hidden-resizer);



resizer.html(This is the text I want to resize.);



while(resizer.width() > desired_width) {

  size = parseInt(resizer.css(font-size), 10);

  resizer.css(font-size, size - 1);

}



$(#target-location).css(font-size, size).html(resizer.html());