Question

Looking for a method to target selected text and perform an action on it in Javascript. What kind of methods should I be using? Is this a job for jQuery? Thanks so much!

EDIT: Earlier answers regarded targeting a CSS class. I’m looking for clicking and highlighting/selecting text and then acting on that in JS. Thanks!

EDIT 2: I’ve been asked for an example of this function. Here’s one but the code has poor reviews. Let me know what you think.

Answer 1

It is quite difficult to write a cross browser, generic “get selected text” function. If you can limit your requirements to say only text selected in a page, then life is simpler.

But if you want to be able to get text selections from anywhere (inside form controls, button labels, general text), then life is tough.

Here’s a function I wrote some time ago, it worked well enough for the application it was used in:

/* 
 *  This function returns the selected text in a document.
 *  If no text selected, returns an empty string.
 *
 *  Call on one of the following events: 
 *
 *     mouseup - most appropriate event
 *               for selection by mousedown, drag to select, mouseup
 *               may select only whitespace
 *
 *    dblclick - not as appropriate as mouseup
 *               for selection of word by double click
 *               may select only whitespace
 *
 *  Note that text can be selected in ways that do not dispatch
 *  an event, e.g. selecting all the text in the document using:
 *     ctrl + a
 *     context menu -> Select All
 *     edit menu -> Select All
 *     programmatically selecting text
 */
function checkForSelectedText(e) {
  var e = e || window.event;
  var el = e.target || e.srcElement;
  var tagName = el.tagName && el.tagName.toLowerCase();
  var t;
  var d = document;

  // Try DOM 2 Range - for most browsers, including IE 6+
  // However, doesn't get text selected inside form controls
  // that allow selection of text content (input type text, 
  // textarea)
  if (d && d.selection && d.selection.createRange) {
    t = d.selection.createRange().text;

  // Otherwise try HTML5 - note that getSelection returns
  // a string with extra properties. This may also get
  // text within input and textarea
  } else if (d.getSelection) {
    t = d.getSelection();
  }

  // If didn't get any text, see if event was inside
  // inupt@type=text or textarea and look for text
  if (t == '') {
    if (tagName == 'textarea' || 
       (tagName == 'input' && el.type == 'text')) {

     // Check selectionStart/End as otherwise if no text
     // selected, IE returns entire text of element
     if (typeof el.selectionStart == 'number' && 
         el.selectionStart != el.selectionEnd) {
        t = el.value.substring(el.selectionStart, el.selectionEnd)
     }
    }
  }
  return t;
}