javascript - 如何从使用 javascript 发布的表单中获取值

Question

我试图使用 javascript 函数提交表单，下面是我的 javascript 函数

   function submit_form(id_textarea,image_name_IN){
//var value_filled_textbox=document.getElementById(textarea_id_in).value;
var form=document.createElement("form_temp");//temporary dummy form
form.setAttribute("method","post");//its a post method
 form.setAttribute("action","comment.php"); // to which the page needs to be submitted

    var comment_value=document.getElementById(id_textarea).value; // gets the content of textarea
   // alert(comment_value);// just to make sure that you are getting the commeted text area content
     //create a hidden field for comments text
            var hiddenField = document.createElement("input");
            hiddenField.setAttribute("type", "hidden");
            hiddenField.setAttribute("name", "comment_content");
          hiddenField.setAttribute("value", comment_value);

           form.appendChild(hiddenField);
        //   create a hidden field for passing image name
        var hiddenField2 = document.createElement("input");
            hiddenField2.setAttribute("type", "hidden");
            hiddenField2.setAttribute("name", "image_name" );
            hiddenField2.setAttribute("value",image_name_IN );

            form.appendChild(hiddenField2);

   document.body.appendChild(form);
    form.submit();
//alert(value_filled_textbox);
window.open("http://127.0.0.1/comment.php");
//document.getElementById('myform').submit();
}

在发表评论时， 我得到了两个comment.php窗口，一个有结果，另一个有两个警告，说未定义的值“image_name”和“comment_content”

Answer 1

It's because form_temp is not a vaild form element. create a just a form element and it will get the submit function

var form=document.createElement("form");//temporary dummy form

Answer 2

Your form must be a <form> ... you used a non-existing HTML element <form_temp> which (of course) doesn't have a submit() method

var form=document.createElement("form");//temporary dummy form

Answer 3

利用

var comment_value=document.getElementById('id_textarea').value;

代替

var comment_value=document.getElementById(id_textarea).value;