如何在不使用元素的 id 的情况下使用 javascript 访问表单元素

How to access form element with javascript without using element's id

提问by Shatadru Bandyopadhyay

I want to access form elements by using javascript. The form is generated dynamically so the name, id of the form and the elements are variable. I want to get the id value of a textareainside it by providing the name of the form, which is generated by a different script.

我想使用 javascript 访问表单元素。表单是动态生成的，因此表单的名称、ID 和元素都是可变的。我想textarea通过提供由不同脚本生成的表单名称来获取其中的 a 的 id 值。

For instance:

例如：

<form method=post name=form33>
    <textarea id=466 cols=50 rows=5></textarea>
    <input name=submit33 onclick=postCmnt(33) value=Post type=button>
</form>

and I have the name of the form name "form33" and I need its textareaid that is 466 as output...

我有表单名称“form33”的名称，我需要它的textareaid 为 466 作为输出...

Javascript Generating The Form:

Javascript 生成表单：

function openComment(id, msgid, div) {
    var div = document.getElementById(div);
    div.innerHTML = "<form method=post name=form"+id+">
        <textarea id="+msgid+" cols=50 rows=5></textarea>
        <input name=submit"+id+" onclick=postCmnt("+id+") value=Post type=button>
        </form>"
}

Javascript that need to access the form

需要访问表单的Javascript

Here is my attempt to access the idname of textareaby providing form name.

这是我通过提供表单名称来访问id名称的尝试textarea。

function postCmnt(id){
    var msgid=document.forms["form"+id].elements[0].id.value;//the text area's id
    var msg=document.getElementById(msgid).value;//value of text area
    //rest scripts goes here        
} 

Information:

信息：

1. Form is not static generated by call to the function openComment()
2. predicting number of form in a page is not possible as it depends upon user input .Though the textarea is the 1st element of the form .

1. 表单不是通过调用函数 openComment() 生成的静态
2. 预测页面中表单的数量是不可能的，因为它取决于用户输入。尽管 textarea 是表单的第一个元素。

采纳答案by Eyal Alsheich

You can add a hidden field that contains the msgid:

您可以添加一个包含 msgid 的隐藏字段：

Javascript Generating The Form:

Javascript 生成表单：

function openComment(id,msgid,div){
    var div = document.getElementById(div);
    div.innerHTML="<form method=post name=form"+id+">
        <input type='hidden' id='theid"+id+"' value='"+msgid+"'>
        <textarea id="+msgid+" cols=50 rows=5></textarea>
        <input name=submit"+id+" onclick=postCmnt("+id+") value=Post type=button>
        </form>"
}

and then just get the value directly:

然后直接获取值：

function postCmnt(id){
    var msgid=document.getElementById("theid"+id).value;//the text area's id
    var msg=document.getElementById(msgid).value;//value of text area
    //rest scripts goes here        
} 

回答by paulusm

If there is only one form in the documents, you can do

如果文件中只有一种形式，您可以这样做

   document.forms[0]

回答by Aravind

As pointed out you can use

正如所指出的，你可以使用

 document.getElementById("teller")[i]

to access the i-th field of the form with id "teller".

访问表单的第 i 个字段，ID 为“teller”。

Demo

演示