How to access id passed via onclick in php

Question

I have been looking from an hour but no luck, I have an JavaScript on-click function on HTML tag. The on-click function redirects me to an another page. The content on the other page will depends on the id passed in the JavaScript on-click event. The problem is I don't know how to access the id in my PHP file so that I can run SQL query to display the data. I don't want the id to be displayed in the URL either.

My HTML on-click element:

<h1 onclick="ContentPage(this.id)" value='.$id.'>'.$title.'</h1>

My javasript function:

<script>
function ContentPage(){

    location.href = "show-content.php";
};
</script>

Answer 1

There are many ways you can go...

Based on your current approach--

Modify your function as such:

function ContentPage(id){
    location.href = "show-content.php?id="+id;
}

The value of id will be in the $_GET variable; specifically of index id

so on your page page,

$passedId = $_GET['id'];

Another approach -- not using inline JS --

<h1 id="myTitle_'.$id.'" class="clickNavigate" value='.$id.'>'.$title.'</h1>

then your JavaScript code becomes

jQuery(".clickNavigate").on("click", function(e) {
    var myID = jQuery(this).attr("id");
    var idParts = myID.split("_");

    location.href = "show-content.php?id="+idParts[1];

});

Answer 2

Fast example using GET, you can also use POST

https://www.tutorialspoint.com/php/php_get_post.htm

HTML

<h1 onclick="ContentPage(this)" value='.$id.' id="myid">'.$title.'</h1>

JAVASCRIPT

<script>
function ContentPage(elem){
    location.href = "show-content.php" + "?id=" + elem.value;
};
</script>

PHP

$id = $_GET["id"];