how - submit form using ajax javascript




JavaScript post request like a form submit (19)

Rakesh Pai's answer is amazing, but there is an issue that occurs for me (in Safari) when I try to post a form with a field called submit. For example, post_to_url("http://google.com/",{ submit: "submit" } );. I have patched the function slightly to walk around this variable space collision.

    function post_to_url(path, params, method) {
        method = method || "post";

        var form = document.createElement("form");

        //Move the submit function to another variable
        //so that it doesn't get overwritten.
        form._submit_function_ = form.submit;

        form.setAttribute("method", method);
        form.setAttribute("action", path);

        for(var key in params) {
            var hiddenField = document.createElement("input");
            hiddenField.setAttribute("type", "hidden");
            hiddenField.setAttribute("name", key);
            hiddenField.setAttribute("value", params[key]);

            form.appendChild(hiddenField);
        }

        document.body.appendChild(form);
        form._submit_function_(); //Call the renamed function.
    }
    post_to_url("http://google.com/", { submit: "submit" } ); //Works!

I'm trying to direct a browser to a different page. If I wanted a GET request, I might say

document.location.href = 'http://example.com/q=a';

But the resource I'm trying to access won't respond properly unless I use a POST request. If this were not dynamically generated, I might use the HTML

<form action="http://example.com/" method="POST">
  <input type="hidden" name="q" value="a">
</form>

Then I would just submit the form from the DOM.

But really I would like JavaScript code that allows me to say

post_to_url('http://example.com/', {'q':'a'});

What's the best cross browser implementation?

Edit

I'm sorry I was not clear. I need a solution that changes the location of the browser, just like submitting a form. If this is possible with XMLHttpRequest, it is not obvious. And this should not be asynchronous, nor use XML, so Ajax is not the answer.


FormObject is an option. But FormObject is not supported by most browsers now.


Here is how I do it.

function redirectWithPost(url, data){
        var form = document.createElement('form');
        form.method = 'POST';
        form.action = url;

        for(var key in data){
            var input = document.createElement('input');
            input.name = key;
            input.value = data[key];
            input.type = 'hidden';
            form.appendChild(input)
        }
        document.body.appendChild(form);
        form.submit();
    }

Here is how I wrote it using jQuery. Tested in Firefox and Internet Explorer.

function postToUrl(url, params, newWindow) {
    var form = $('<form>');
    form.attr('action', url);
    form.attr('method', 'POST');
    if(newWindow){ form.attr('target', '_blank'); 
  }

  var addParam = function(paramName, paramValue) {
      var input = $('<input type="hidden">');
      input.attr({ 'id':     paramName,
                 'name':   paramName,
                 'value':  paramValue });
      form.append(input);
    };

    // Params is an Array.
    if(params instanceof Array){
        for(var i=0; i<params.length; i++) {
            addParam(i, params[i]);
        }
    }

    // Params is an Associative array or Object.
    if(params instanceof Object) {
        for(var key in params){
            addParam(key, params[key]);
        }
    }

    // Submit the form, then remove it from the page
    form.appendTo(document.body);
    form.submit();
    form.remove();
}

I'd go down the Ajax route as others suggested with something like:

var xmlHttpReq = false;

var self = this;
// Mozilla/Safari
if (window.XMLHttpRequest) {
    self.xmlHttpReq = new XMLHttpRequest();
}
// IE
else if (window.ActiveXObject) {
    self.xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
}

self.xmlHttpReq.open("POST", "YourPageHere.asp", true);
self.xmlHttpReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');

self.xmlHttpReq.setRequestHeader("Content-length", QueryString.length);



self.xmlHttpReq.send("?YourQueryString=Value");

If you have Prototype installed, you can tighten up the code to generate and submit the hidden form like this:

 var form = new Element('form',
                        {method: 'post', action: 'http://example.com/'});
 form.insert(new Element('input',
                         {name: 'q', value: 'a', type: 'hidden'}));
 $(document.body).insert(form);
 form.submit();

No, you cant have the JavaScript post request like a form submit.

What you can have is a form in HTML, then submit it with the JavaScript. (as explained many times on this page)

You can create the HTML yourself, you don't need JavaScript to write the HTML. That would be silly if people suggested that.

<form id="ninja" action="http://example.com/" method="POST">
  <input id="donaldduck" type="hidden" name="q" value="a">
</form>

Your function would just configure the form the way you want it.

function postToURL(a,b,c){
   document.getElementById("ninja").action     = a;
   document.getElementById("donaldduck").name  = b;
   document.getElementById("donaldduck").value = c;
   document.getElementById("ninja").submit();
}

Then, use it like.

postToURL("http://example.com/","q","a");

But I would just leave out the function and just do.

   document.getElementById('donaldduck').value = "a";
   document.getElementById("ninja").submit();

Finally, the style decision goes in the ccs file.

.ninja{ 
  display:none;
}

Personally I think forms should be addressed by name but that is not important right now.


One solution is to generate the form and submit it. One implementation is

function post_to_url(url, params) {
    var form = document.createElement('form');
    form.action = url;
    form.method = 'POST';

    for (var i in params) {
        if (params.hasOwnProperty(i)) {
            var input = document.createElement('input');
            input.type = 'hidden';
            input.name = i;
            input.value = params[i];
            form.appendChild(input);
        }
    }

    form.submit();
}

So I can implement a URL shortening bookmarklet with a simple

javascript:post_to_url('http://is.gd/create.php', {'URL': location.href});

The easiest way is using Ajax Post Request:

$.ajax({
    type: "POST",
    url: 'http://www.myrestserver.com/api',
    data: data,
    success: success,
    dataType: dataType
    });

where:

  • data is an object
  • dataType is the data expected by the server (xml, json, script, text, html)
  • url is the address of your RESt server or any function on the server side that accept the HTTP-POST.

Then in the success handler redirect the browser with something like window.location.


The method I use to post and direct a user automatically to another page is to just write a hidden form and then auto submit it. Be assured that the hidden form takes absolutely no space on the web page. The code would be something like this:

    <form name="form1" method="post" action="somepage.php">
    <input name="fielda" type="text" id="fielda" type="hidden">

    <textarea name="fieldb" id="fieldb" cols="" rows="" style="display:none"></textarea>
</form>
    document.getElementById('fielda').value="some text for field a";
    document.getElementById('fieldb').innerHTML="some text for multiline fieldb";
    form1.submit();

Application of auto submit

An application of an auto submit would be directing form values that the user automatically put in on the other page back to that page. Such an application would be like this:

fieldapost=<?php echo $_post['fielda'];>
if (fieldapost !="") {
document.write("<form name='form1' method='post' action='previouspage.php'>
  <input name='fielda' type='text' id='fielda' type='hidden'>
</form>");
document.getElementById('fielda').value=fieldapost;
form1.submit();
}

This is like Alan's option 2 (above). How to instantiate the httpobj is left as an excercise.

httpobj.open("POST", url, true);
httpobj.setRequestHeader('Content-Type','application/x-www-form-urlencoded; charset=UTF-8');
httpobj.onreadystatechange=handler;
httpobj.send(post);

This works perfectly in my case:

document.getElementById("form1").submit();

You can use it in function like:

function formSubmit() {
     document.getElementById("frmUserList").submit();
} 

Using this you can post all the values of inputs.


Three options here.

  1. Standard JavaScript answer: Use a framework! Most Ajax frameworks will have abstracted you an easy way to make an XMLHTTPRequest POST.

  2. Make the XMLHTTPRequest request yourself, passing post into the open method instead of get. (More information in Using POST method in XMLHTTPRequest (Ajax).)

  3. Via JavaScript, dynamically create a form, add an action, add your inputs, and submit that.


Using the createElement function provided in this answer, which is necessary due to IE's brokenness with the name attribute on elements created normally with document.createElement:

function postToURL(url, values) {
    values = values || {};

    var form = createElement("form", {action: url,
                                      method: "POST",
                                      style: "display: none"});
    for (var property in values) {
        if (values.hasOwnProperty(property)) {
            var value = values[property];
            if (value instanceof Array) {
                for (var i = 0, l = value.length; i < l; i++) {
                    form.appendChild(createElement("input", {type: "hidden",
                                                             name: property,
                                                             value: value[i]}));
                }
            }
            else {
                form.appendChild(createElement("input", {type: "hidden",
                                                         name: property,
                                                         value: value}));
            }
        }
    }
    document.body.appendChild(form);
    form.submit();
    document.body.removeChild(form);
}

Yet another recursive solution, since some of others seem to be broken (I didn't test all of them). This one depends on lodash 3.x and ES6 (jQuery not required):

function createHiddenInput(name, value) {
    let input = document.createElement('input');
    input.setAttribute('type','hidden');
    input.setAttribute('name',name);
    input.setAttribute('value',value);
    return input;
}

function appendInput(form, name, value) {
    if(_.isArray(value)) {
        _.each(value, (v,i) => {
            appendInput(form, `${name}[${i}]`, v);
        });
    } else if(_.isObject(value)) {
        _.forOwn(value, (v,p) => {
            appendInput(form, `${name}[${p}]`, v);
        });
    } else {
        form.appendChild(createHiddenInput(name, value));
    }
}

function postToUrl(url, data) {
    let form = document.createElement('form');
    form.setAttribute('method', 'post');
    form.setAttribute('action', url);

    _.forOwn(data, (value, name) => {
        appendInput(form, name, value);
    });

    form.submit();
}

You could dynamically add the form using DHTML and then submit.



jQuery plugin for redirect with POST or GET:

https://github.com/mgalante/jquery.redirect/blob/master/jquery.redirect.js

To test, include the above .js file or copy/paste the class into your code, then use the code here, replacing "args" with your variable names, and "values" with the values of those respective variables:

$.redirect('demo.php', {'arg1': 'value1', 'arg2': 'value2'});

 /**
 * sends a request to the specified url from a form. this will change the window location.
 * @param {string} path the path to send the post request to
 * @param {object} params the paramiters to add to the url
 * @param {string} [method=post] the method to use on the form
 */

function post(path, params, method) {
    method = method || "post"; // Set method to post by default if not specified.

    // The rest of this code assumes you are not using a library.
    // It can be made less wordy if you use one.
    var form = document.createElement("form");
    form.setAttribute("method", method);
    form.setAttribute("action", path);

    for(var key in params) {
        if(params.hasOwnProperty(key)) {
            var hiddenField = document.createElement("input");
            hiddenField.setAttribute("type", "hidden");
            hiddenField.setAttribute("name", key);
            hiddenField.setAttribute("value", params[key]);

            form.appendChild(hiddenField);
        }
    }

    document.body.appendChild(form);
    form.submit();
}

Example:

post('/contact/', {name: 'Johnny Bravo'});

EDIT: Since this has gotten upvoted so much, I'm guessing people will be copy-pasting this a lot. So I added the hasOwnProperty check to fix any inadvertent bugs.







html-form