我试图获取动态选择的选定索引的值.JavaScript

我正在为我的教会开发一个动态表单，在我尝试获取动态选择的选定索引的值之前，我没有任何问题。下面是生成选择的代码块以及用于尝试访问、检索值的测试函数。我真的很感激你能提供的任何帮助。我浏览了我的代码书库，在网上搜索了好几天，找不到任何可以解决问题的东西。我可以从动态文本框中检索用户输入，但无法从选择中获取任何内容。

感谢您的时间和帮助。如果您想查看完整的源代码 完整的 JavaScript 代码

/***

var t_shirt = 0;
    for(var i = 0; i < 1; i++){
        var cell = document.createElement('td');
        var t_shirt_size = document.createElement('select');
        t_shirt_size.setAttribute('name','t_shirt_size');
        t_shirt_size.setAttribute('id','t_shirt'+t_shirt);
        t_shirt_size.setAttribute('class','dynamic_select_shirt');
        var topt0 = document.createElement('option');
        topt0.setAttribute('id','option0');
        topt0.setAttribute('value','T-Shirt Size');
        topt0.innerHTML = 'T-Shirt Size';
        var topt1 = document.createElement('option');
        topt1.setAttribute('id','option1');
        topt1.setAttribute('value','Youth Small');
        topt1.innerHTML = 'Youth Small';
        var topt2 = document.createElement('option');
        topt2.setAttribute('id','option2');
        topt2.setAttribute('value','Youth Medium');
        topt2.innerHTML = 'Youth Medium';
        var topt3 = document.createElement('option');
        topt3.setAttribute('id','option3');
        topt3.setAttribute('value','Youth Large');
        topt3.innerHTML = 'Youth Large';
        var topt4 = document.createElement('option');
        topt4.setAttribute('id','option4');
        topt4.setAttribute('value','Youth X-Large');
        topt4.innerHTML = 'Youth X-Large';
        var topt5 = document.createElement('option');
        topt5.setAttribute('id','option5');
        topt5.setAttribute('value','Adult Small');
        topt5.innerHTML = 'Adult Small';
        var topt6 = document.createElement('option');
        topt6.setAttribute('id','option6');
        topt6.setAttribute('value','Adult Medium');
        topt6.innerHTML = 'Adult Medium';
        var topt7 = document.createElement('option');
        topt7.setAttribute('id','option7');
        topt7.setAttribute('value','Adult Large');
        topt7.innerHTML = 'Adult Large';
        var topt8 = document.createElement('option');
        topt8.setAttribute('id','option8');
        topt8.setAttribute('value','Adult X-Large');
        topt8.innerHTML = 'Adult X-Large';
        t_shirt++;
        //alert('made it past ++ topt ');
        t_shirt_size.appendChild(topt0);
        t_shirt_size.appendChild(topt1);
        t_shirt_size.appendChild(topt2);
        t_shirt_size.appendChild(topt3);
        t_shirt_size.appendChild(topt4);
        t_shirt_size.appendChild(topt5);
        t_shirt_size.appendChild(topt6);
        t_shirt_size.appendChild(topt7);
        t_shirt_size.appendChild(topt8);
        cell.appendChild(t_shirt_size);            
        row.appendChild(cell);
    }    

    table_body.appendChild(row);

}
table_nop.appendChild(table_body);
mul.appendChild(table_nop);

table_nop.setAttribute('id','dynamic_table_main');
document.getElementById('form_div').style.display='block';

/**** 我尝试用来检索值的代码。/***

    function a(){
    var cname = document.getElementById('tbNAME'+0).value;
        var cbd = document.getElementById('tbBD'+0).value;
        var cAORD = document.getElementById('tbAORD'+0).value;
        var cgender = document.getElementById('gender_select'+0).selectedIndex;
        var cshirt = document.getElementById('t_shirt'+0);

alert(cshirt.length);
}

function check_dynamic_table(){
        var errorc = 0;
        var nop = check_id_global;
        for(var i =0; i < nop;i++){
        var cname = document.getElementById('tbNAME'+i).value;
        var cbd = document.getElementById('tbBD'+i).value;
        var cAORD = document.getElementById('tbAORD'+i).value;
        var cgender = document.getElementById('gender_select'+i).value;
        var cshirt = document.getElementById('t_shirt'+i).value;
        if(cname == "" || cname == null){
         alert('Please Fill Out All Fields:' +cname );
        }
        if(cbd == "" || cbd == null){
         alert('Please Fill Out All Fields:'+cbd);
        }
        if(cAORD == "" || cAORD == null){
            alert('Please Fill Out All Fields:'+cAORD);
        }
        if(cgender == 'gender'){
            alert('Please make a Gender Selection:'+cgender);
        }
        if(cshirt == 'T-Shirt Size'){
            alert('Please make a T-Shirt Selection:'+cshirt);
        }
        }
}