phpform表单里的判断,该如何解决

function sendData(){
    var uid=document.getElementById('hidden_uid').value;
    var sid = document.getElementById('hidden_sid').value;
    var text = document.getElementById('part_text').value;
    var rideo = document.getElementsByName('part[is_good]');
    var is_good;
    if(text == '' || text == '输入您的看法,字数在50字内'){
        alert('请提出您的看法,不然投票无效哦!');
        return false;
    }
    alert (sid);
    for(var i=0; i