source: extensions/SmiliesSupport/smiliessupport.js @ 8550

var theSelection = false;

function SmiliesWrite(form, field, start, end, force) {
        var textarea = document.forms[form].elements[field];    
        
        storeCaret(textarea);
        
        if (textarea.caretPos) {
          textarea.focus();
                // Attempt to create a text range (IE).
                theSelection = document.selection.createRange().text;           
                if (force || theSelection != '') {
                        document.selection.createRange().text = start + theSelection + end;
                        textarea.focus();
                        return true;
                }
        } else if (typeof(textarea.selectionStart) != "undefined") {
                // Mozilla text range replace.
                var text = new Array();
                text[0] = textarea.value.substr(0, textarea.selectionStart);
                text[1] = textarea.value.substr(textarea.selectionStart, textarea.selectionEnd-textarea.selectionStart);
                text[2] = textarea.value.substr(textarea.selectionEnd);
                caretPos = textarea.selectionEnd+start.length+end.length;
                if (force || text[1] != '') {
                        textarea.value = text[0]+start+text[1]+end+text[2];
                        if (textarea.setSelectionRange) {
                                textarea.focus();
                                textarea.setSelectionRange(caretPos, caretPos);
                        }
                        return true;
                }
        } else if (force) {             
                // Just put it on the end.
                textarea.value += start+end;
                textarea.focus(textarea.value.length-1);
                return true;
        }
        return false;
}

function storeCaret(text) {
        if (text.createTextRange) text.caretPos = document.selection.createRange().duplicate();
}