jQuery.fn.extend({  
    getCurPos: function(){  
        var e=$(this).get(0);  
        e.focus();  
        if(e.selectionStart){    //FF  
            return e.selectionStart;  
        }  
        if(document.selection){    //IE  
            var r = document.selection.createRange();  
            if (r == null) {  
                return e.value.length;  
            }  
            var re = e.createTextRange();  
            var rc = re.duplicate();  
            re.moveToBookmark(r.getBookmark());  
            rc.setEndPoint('EndToStart', re);  
            return rc.text.length;  
        }  
        return e.value.length;  
    },  
    setCurPos: function(pos) {  
        var e=$(this).get(0);  
        e.focus();  
        if (e.setSelectionRange) {  
            e.setSelectionRange(pos, pos);  
        } else if (e.createTextRange) {  
            var range = e.createTextRange();  
            range.collapse(true);  
            range.moveEnd('character', pos);  
            range.moveStart('character', pos);  
            range.select();  
        }  
    }          
});