a/20570055/1636522

by wared

HTML

<p><i>Click a word.</i></p>
<textarea readonly>Lorem ipsum          dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</textarea>

CSS

body, textarea {
    font: normal 16px Arial;
}
i {
    color: gray;
}
textarea {
    display: block;
    width: 100%;
    border: none;
    resize: none;
    outline: none;
    margin: .5em 0;
}

JavaScript

var el = $('textarea'),
    text = el.text();
el.click(function () {
    var i = getCaret(this),
        w = getWord(text, i);
    $('p').text('"' + w + '" (index : ' + i + ')');
});

// http://stackoverflow.com/a/995374/1636522

el[0].style.height = '1px';
el[0].style.height = 25 + el[0].scrollHeight + 'px';

function getWord(s, i) {
    var r = /\s/g;
    while (i && !r.test(s[--i])) {}
    r.lastIndex = i && ++i;
    return s.slice(i, (
        r.exec(s) || { index: s.length }
    ).index);
}

// http://stackoverflow.com/a/263796/1636522

function getCaret(el) {
    if (el.selectionStart) {
        return el.selectionStart;
    } else if (document.selection) {
        el.focus();
        var r = document.selection.createRange();
        if (r == null) {
            return 0;
        }
        var re = el.createTextRange(),
            rc = re.duplicate();
        re.moveToBookmark(r.getBookmark());
        rc.setEndPoint('EndToStart', re);
        return rc.text.length;
    }
    return 0;
}