java 和 javascript中空值和字符串的比较

//校验名称和日期不为空
function checksave(){
var sname=document.getElementById("sname").value;
var stime=document.getElementById("datetimepicker1").value;
var etime=document.getElementById("datetimepicker2").value;
if(sname=="" )
{
alert("名字不能为空!") ;
return false;
}
if ((stime=="") || (etime=="") ){
alert("开始或结束时间不能为空!") ;
return false;
}
}

if ("".equals(product.getName()) ){

if(product.getSmallClassId()== -9999){

specialVos= specialService.getSpecialVos(special.getId());

}else{

specialVos= specialService.getSpecialVos(special.getId(),product.getSmallClassId());

}
}

if (special.getId()==null){
special.setId(idGenerator.incr(Special.class));
special.setCreateDate(new Date());
special.setCreateUser((long) 110);
specialService.saveSpecial(special);
}