Retrive post data back using javascript/jquery - javascript

I want to pass the object to the new page by using only client side script(javascript),
and I want to read the data back when the new page is loads, but I could not find any tutorial or method to get it.
function postToURL(path, parameters) {
var form = $('<form></form>');
form.attr("method", "post");
form.attr("action", path);
$.each(parameters, function(key, value) {
var field = $('<input></input>');
field.attr("type", "hidden");
field.attr("name", key);
field.attr("value", value);
form.append(field);
});
// The form needs to be a part of the document in
// order for us to be able to submit it.
$(document.body).append(form);
form.submit();
}

The POST message sent to the server to retrieve the current page is not exposed, by the browser, to JavaScript in that page, so you cannot.
Pass the data via some other technique (such as through the URL, or localstorage).

Yeah, POST data is only handled and seen by the server side (ex. PHP). Javascript is on the client side so it will never be able to see that data unless the POST data first gets passed to server side and that server side in turn hands it off to the client side (ex. Javascript).
Consider using GET as your method in your code above so that you can pass the parameters inside the actual URL to make it accessible to the browser / client / Javascript.

parameters can be parsed from a JSON-encoded string. If you build your parameters programmically (in the previous step) like:
parameters = {};
parameters['USA'] = 'Washington DC';
parameters['UK'] = 'London';
You can create a flat JSON String representing your structured data by:
parametersString = JSON.stringify(parameters);
and end up with something like this:
"{'USA': 'Washington DC', 'UK': 'London'}"
You can store this string in a cookie, or in a query string or fragment part of the URL.
Your next page can read back this value on the following page, and re-create the structured parameters by decoding the JSON string like:
parameters = JSON.parse(parametersString);
and you're getting the original data back, on which you can run JQuery's each.

Related

in Rails, How to make a query in javascript?

Given the id of an element I need to make a query in javascript, for example:
javascript:
var post_value = $(".post").val() # return a post ID;
var post = #{Post.find_by(id: post_value).to_json.html_safe};
But the post_value variable don't recognize it
If I manually pass a value to it, it recognizes it and asks me the query of the post, for example:
var post = #{Post.find_by(id: 181).to_json.html_safe}; # If work because I pass 181 as an ID value
I would be very grateful if you could help me
This line gets rendered in server side. It will not have any access to the browser's runtime context. As this gets executed before reaching the user.
var post = #{Post.find_by(id: post_value).to_json.html_safe};
Either use XHR (have another endpoint API purely for data objects like json) or query your Post object/s in controller, pass the object to the view and render the Post object inside the view. It is also a bad practice to have DB queries inside the view template files.
It's also weird to use javascript to render elements in the backend context. You generally use javascript with the context or assumption that it is to be executed in the user's side, separated with the backend context.

passing js value to another php page using java script and receiving value

I want to to pass a js variable to another page ..what to do..code is given bellow..
Code
`
$('#disInfo').on('click','tr',function(){
var obj = $(this);
var result= obj.find('td').eq(1).html();
window.location.href='http://localhost/Trying/search_cus.php';
});
`
I want to send the value of result variable with page link and how to receive the value in another page
You could pass it via an url parameter. If result contains html or characters that cannot be used in an url then you need to encode it first.
$('#disInfo').on('click','tr',function(){
var obj = $(this);
var result = encodeURIComponent( obj.find('td').eq(1).html() );
window.location.href='http://localhost/Trying/search_cus.php?result=' + result;
});
On the target page you can get url parameters via window.location.search ... there's plenty of examples on stackoverflow on how to do that.
NOTE: be aware that the server will also get the request for ?result=whatever. If the server side code processes this (eg PHP: $_GET['result']) you must ensure it sanitizes the value to prevent malicious code injection.
BTW, other ways of passing data is via cookies, sessionStorage, localStorage, etc.

Sending and getting data via $.load jquery

I'm writing a system in HTML5 and Javascript, using a webservice to get data in database.
I have just one page, the index.html, the other pages i load in a <div>
The thing is, i have one page to edit and add new users.
When a load this page for add new user, i do this:
$("#box-content").load("views/motorista_add.html");
But, i want send a parameter or something else, to tell to 'motorista_add.html' load data from webservice to edit an user. I've tried this:
$("#box-content").load("views/motorista_add.html?id=1");
And i try to get using this:
function getUrlVar(key) {
var re = new RegExp('(?:\\?|&)' + key + '=(.*?)(?=&|$)', 'gi');
var r = [], m;
while ((m = re.exec(document.location.search)) != null)
r.push(m[1]);
return r;
}
But don't work.
Have i an way to do this without use PHP?
This won't work. Suppose your are loading the motorista_add.html in a page index.html. Then the JS code, the function getUrlVar(), will execute on the page index.html. So document.location that the function will get won't be motorista_add.html but index.html.
So Yes. To do the stuff you are intending, you need server side language, like PHP. Now, on the server side, you get the id parameter via GET variable and use it to build up your motorista_add.php.
You can pass data this way:
$("#box-content").load("views/motorista_add.html", { id : 1 });
Note: The POST method is used if data is provided as an object (like the example above); otherwise, GET is assumed. More info: https://api.jquery.com/load/

How to pass value to another static page via javascript?

I am trying to pass value to another page and read the value in the another page. I use only JavaScript and jQuery. Not use others language as PHP. I don't want to be as like (http://www.example.com/?value=test). I am trying to use POST or GET method.
On first page:
$.post("second_page.html",{q:"test"});
window.location.replace("second_page.html");
On second page:
var location_query = window.location.search.substring(1);
var vars = location_query.split("&");
for (var i in vars) {
var param = vars[i].split("=");
params[param[0].toString()] = param[1];
}
If I pass value as like http://www.example.com/?q=test , the second page script is read the value, but I use this line: $.post("second.html",{q:"test"}); not read.
How to pass value from first page to another static page via JavaScript or jQuery or ajax?
See this post says:
POST data is data that is handled server side. And Javascript is on client side. So there is no way you can read a post data using JavaScript.
but you can use cookies to read and store values:
<script src="/path/to/jquery.cookie.js"></script>
you can get it from here
Try with reading the documentation and see if this works for you.
Without using GET or POST you can transfer the content using HTML5 Local Storage or
Web SQL
$.post and $.get send AJAX request and waiting response on current page, you cant send params for next window.location.replace by this.
Use url get-params window.location.replace("404.html?q=404"); and look this for get params on second page.

How can one incorporate JSON data with the returned HTML on the first request to the home page?

My scenario is this - the user asks for the home page and then the javascript code of the page executes an ajax GET request to the same server to get some object.
The server keeps the home page as a jade template.
So, right now it takes two roundtrips to load the home page:
GET the home page
GET the JSON object
I am OK with it, but just out of curiosity - what are my options to incorporate the object requested later into the initial GET request of the home page?
I see one way is to have a hidden html element, which inner HTML would be the string representation of the object. A bit awkward, but pretty simple on the server side, given that the home page jade template is preprocessed anyway.
What are my other options?
Please, note that I am perfectly aware that sparing this one roundtrip does not really matter. I am just curious about the techniques.
Another option is to always return a JSON object, then the HTML for your home page would be the value of some property on this object. This would probably require some changes on your client-side logic, though.
One more option: instead of a hidden HTML input/textarea containing a JSON string, the home page code could contain a script block where an object literal is declared as a variable. Something like this:
<script>
var myObj = ... // Your JSON string here.
// myObj will be an object literal, and you won't need
// to parse the JSON.
</script>
The initial GET request will retrieve just that document. You can have additional documents loaded defined as scripts at the bottom of your page, so you don't need to do a XHR, for the initial load.
For instance:
GET /index.html
//At the bottom you have a <script src="/somedata.js"></script>
GET /somedata.js
//here you define you var myObj = {}.... as suggested by bfavertto
Depending on which server side technology are you using, this could be for instance in MVC3
public partial class SomeDataController : BaseController
{
public virtual ContentResult SomeData()
{
var someObject = //GET the JSON
return Content("var myObj = " + someObject, "application/javascript");
}
}
You can embed the Json data inside a hidden tag in your HTML. At runtime, your javascript reads the data from this hidden tag instead of making a Json call (or make the call if this data is not available).
<!--the contents of this div will be filled at server side with a Json string-->
<div id="my-json-data" style="display:hidden">[...json data...]</div>
on document ready:
var jsonStr = document.getElementById( "my-json-data" ).innerHTML;

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