js 判断

//判断时间格式
function isDateTime(e)
{
    var timeReg = /^\d{4}\-\d{1,2}\-\d{1,2}$/;
    if (!timeReg.test(e.value))
    {
        alert("时间输入错误?请重新输入!");
        return false;
    }
    return true;
}

//判断邮箱地址格式
function isEmail(e)
{
    var setReg=/[_a-zA-Z\d\-\.]+@[_a-zA-Z\d\-]+(\.[_a-zA-Z\d\-]+)+$/;
    if(!setReg.test(e.value))
    {
        alert("Email地址错误!请重新输入。");
        return false;
    }
    return true;
}
//判断字段是否为空
<form id="chekUserForm" name="chekUserForm" method="post" action="" onsubmit="return checkFrom();">
</form>
function checkFrom()
{
    var _lef = "ctl00_ContentPlaceHolder1_";
    var NM=['txtuser','txtPwd','txtEN','txtCNS','txtEmail','txtContact'];
    var NT=['用户名','密码','英文名','中文名','邮箱地址','联系人资料'];
    for(var i = 0;i < NM.length;i++)
    {
        var _pctr = document.getElementById(_lef + NM[i]);
        if(_pctr.value=='')
        {
            alert(NT[i]+'不能为空!');
            _pctr.focus();
            return false;
        }
    }
    var name=['DDListDepart','DDListDuty'];
    var nt=['部门','职务'];
    for(var i=0;i<name.length;i++)
    {
        var _name=document.getElementById(_lef+name[i]);
        var select=_name.options[_name.selectedIndex].value;
        if(select=="")
        {
            alert(nt[i]+'没有选择!');
            _name.focus();
            event.returnValue=false;
            return false;
        }
                    
    }    
    return true;
}
//去掉字符串最后一个字符
var str="1,2,3,4,5,";
1.str=str.substring(0,str.length-1);
2.str=str.substr(0,str.length-1);