[求助]JS的问题??
JS中空格怎么判断,我用addForm.username.length=0不行,怎么写??
<script language="javascript">
function check()
{
if(addForm.username.value == null || addForm.username.value=="" )
{
alert("用户名不能为空!");
return false;
}
if(addForm.password.value == null || addForm.password.value=="" || addForm.password.length=0)
{
alert("密码不能为空!");
return false;
}
if(addForm.truename.value == null || addForm.truename.value=="" || addForm.truename.length=0)
{
alert("真实姓名不能为空!");
return false;
}
return true;
}
</script>