Changing php variable by java script

Question

I have a button with onclick function. It passes a variable $x into the java script. Shortly what i want to do is to pass the $x="aaa" to the javascript, and make the function to change this variable into lets say $x="bbb" without refreshing the website. So i would be able to click it all the time and the js could change the value of given variable. I mean the content variable going from button to javascript would be changed depending on js function code. This may sound complicated i am really sorry for that. Any ideas? (the code below i just made up because it would be to long to explain here all my code that is very long now)

<?php x = "aaa";  ?>

<button onClick="someFunction(<?php $x ?>)"></button>

<script> 
function someFunction (x){
//what can i do here to make this "aaa" string in variable change 
//into for example "bbb" on clicking it again?
}
</script>

possible duplicate of [How to pass JavaScript variables to PHP?](http://stackoverflow.com/questions/1917576/how-to-pass-javascript-variables-to-php) — Dave, Aug 11 '15 at 21:22

Anik Islam Abhi · Accepted Answer · 2015-08-11T21:46:08.590

1

You can't change server side language value from client script

All you can do is to pass that php value to javascript

Like this

<button onClick="someFunction(<?php echo $x; ?>)"></button>

But you can do like it

Try like this

js

$.ajax({
  method: "GET",
  url: "some.php",
  data: { x: "John" }
})
  .done(function( msg ) {
    <?php x=$_COOKIE["X"]; ?>
});

some.php

$_COOKIE["X"]=$_GET["x"];

EDIT

How I can cut it off from button arguments

HTML

<button id="myButton" onclick="someFunction(<?php $x ?>)"></button>

JS

$("#myButton").on("click",function(){
    var onclick=$(this).attr("onclick");
    var str="Hellow world";
    var someFunction="someFunction('"+str+"')";
    $(this).attr("onclick",someFunction);
});

edited Aug 11 '15 at 21:46

answered Aug 11 '15 at 21:21

Anik Islam Abhi

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and ajax cant do this? its asynchronious thing. – UberProCoder Aug 11 '15 at 21:23
yea you can do it but not direct way. like say you have database in ajax you pass that value to another php . that php file save that in database and another ajax retrive these value from database. – Anik Islam Abhi Aug 11 '15 at 21:24
damn thats pretty sad, I was hoping that js got some more power. Cant i Just manipulate the onclick values? – UberProCoder Aug 11 '15 at 21:25
like i said before , you can't directly do that but indirect way you can do that . like instead of database you can use cookies change that cookie value in ajax and after call that you can simply assign cookie value in your x . – Anik Islam Abhi Aug 11 '15 at 21:28
But i mean.. i dont need this $x variable. I can cut it off from button arguments. Just want to pass another string into onclick. It is all going on client side right? How to make this $x disapear and replace it with any string? – UberProCoder Aug 11 '15 at 21:30
Ohh the thing with cookie is helpful as well then you! – UberProCoder Aug 11 '15 at 21:33
yeah you can easily do that easily in client `I can cut it off from button arguments` – Anik Islam Abhi Aug 11 '15 at 21:34
Could you please advice me what should i read about in order to change the content of onclick from inside of js or jquery please? I already gave you the best answer mark :D:D! – UberProCoder Aug 11 '15 at 21:37
is Jquery allowed in your project ? – Anik Islam Abhi Aug 11 '15 at 21:38
Yes, it is but i am very bad in js coding, have some hard beginnings – UberProCoder Aug 11 '15 at 21:39
Thank you a lot! i will give you + as soon as i get my first points! you are great dude – UberProCoder Aug 11 '15 at 21:47

score 0 · Answer 2 · answered Aug 11 '15 at 21:51

With the above code in mind... Not knowing if it is specifically strings that you wish to manipulate with javascript but you can use php / a server side language to generate the variable value based upon whatever calculations you need and then use javascript to play with it on the client side.

<button onClick="someFunction()">Click me now to see what happens to x</button>


<script>
<?php echo "var x = 'a';";  ?>
function someFunction(){
    x=parseInt( x.charCodeAt(0) );
    x++;
    x=String.fromCharCode( x );
    alert(x)
}
</script>

Damn this looks genius. And they say its bad to combine php and js haa! — UberProCoder, Aug 11 '15 at 22:16

score 0 · Answer 3 · answered Jul 27 '21 at 10:29

After research and other's help, this works :

//This gets the page's width on the first load
let sWidth = window.screen.width;

//This says : execute "myfunction" when "resize" event occurs
window.addEventListener("resize", myFunction);

//details of myFunction
function myFunction() {
    //first get the page's width again
    let sWidth = window.screen.width;

    //show me the page's width within console which is within inspect
    console.log(sWidth);

    //now this is for differentiating Mobile and Desktop version
    //which you can change the statement by need
    if (sWidth <= 576){
        console.log("Mobile version");
    }else{
        console.log("Desktop version");
    }
}

Changing php variable by java script

3 Answers3