var _context = "用户名/邮箱/手机";
$(document).ready(function() {

    try {
        var __username = _username;
    } catch (e) {
    }

    if (__username) {

        $("#" + __username).focus(function() {
            if ($("#" + __username).attr("value") == _context)
                $("#" + __username).attr("value", "");
        });

        $("#" + __username).blur(function() {
            if ($("#" + __username).attr("value") == "")
                $("#" + __username).attr("value", _context);
        });

        $("#" + __username).keydown(function(event) {
            if (event.keyCode == 13) {
                //$("#" + _password).focus();
                //            event.returnValue = false;
                //            event.cancel = true;

                return false;
            }
        });

        $("#" + _password).keydown(function(event) {
            if (event.keyCode == 13) {
                $("#" + _loginButton).click();
            }
        });

        if (!$("#" + __username).attr("value"))
            $("#" + __username).attr("value", _context);
    }
})