/**
 * 选择所有当前form内的checkbox
 */
function selectAll(self) {
    $this = $(self);
    $inputs = $this.parents('form').find('input:checkbox');
    if ($this.attr('checked')) {
        $inputs.attr('checked', 'checked');
    } else {
        $inputs.removeAttr('checked')
    }
}

function doPost(self, action) {
    $this = $(self);
    $form = $this.parents('form');
    $form.attr('action', action);
    $form.submit();
    return false;
}

function checkletter(){
     document.getElementById("lettercon").value = document.getElementById("content").value.length+" characters";
}

function showDiv(id) {
    $(id).toggle();
}

function ieVersion() {
    //fxxk IE6!
    var ie = (function(){
        var undef,
            v = 3,
            div = document.createElement('div'),
            all = div.getElementsByTagName('i');
        while (
            div.innerHTML = '<!--[if gt IE ' + (++v) + ']><i></i><![endif]-->',
            all[0]
        );
        return v > 4 ? v : undef;

    }());

    return ie;
}

function loopColor(items, class1, class2) {
    class1 = class1 || 'color1';
    class2 = class2 || 'color2';
    var _class = class1;
    $.each(items, function() {
        $(this).addClass(_class);
        _class = _class != class2 ? class2 : class1;
    });
}

function changeDisplay(style) {
    if(currentDisplayStyle != style) {
        $('.' + currentDisplayStyle).hide();
        $('.' + style).show();
        currentDisplayStyle = style;
    }
}