Using PHP in Javascript

Question

I just found out that PHP can be used in Javascript like this:

<script>
function seeTime() {
alert("<?php echo time(); ?>");
}
</script>
<button onclick="seeTime();">Click Me</button>

The above code will popup an alert message with the Unix timestamp every time the button "Click Me" is clicked. But the problem is, the time remains the same everytime you click the button until the page is reloaded.

I know AJAX is the solution but is there any other way I can update the data inside the javascript code/file without using any external php file to fetch data from it with AJAX ?

• Marc B: you do realize that PHP runs on the server? It'll embed the timestamp AT THE TIME THE PAGE WAS GENERATED, and then php cannot do ANYHING to the page. how about alert(Math.floor(new Date().getTime() / 1000))?
• SLaks: No; PHP cannot be used in Javascript. You can use PHP to create Javascript. Look at the generated source.
• Rehan: @SLaks I thought about it. But how am I supposed to connect the just now created js file with my already loaded page? Thinking that the JS file is temporary and will be deleted after the user for whom it was created has left my website.

Answer 1

I know AJAX is the solution but is there any other way I can update the data inside the javascript code/file without using any external php file to fetch data from it with AJAX ?

Yes, just don't use PHP at all:

function seeTime() {
 alert(Math.floor(new Date().getTime()/1000));
}

• Rehan: It's not about time. What if it's an User's friend's last logged in time? I can't do it with pure javascript, can I ?
• danronmoon: This is the number of milliseconds since the Unix epoch, not the number of seconds.
• bfavaretto: @Rehan I believe you should add more details to your question, then. Please explain what you're really trying to accomplish.
• bfavaretto: @danronmoon True, added some math to convert to seconds.

Answer 2

You are getting confused between PHP and JavaScript. PHP is not being "used" in JavaScript. PHP runs on the server and generates the page, which is then sent to the browser.

<?php echo time(); ?> is replaced with the current timestamp, then sent to the browser which runs the JavaScript.

Answer 3

As far as I know it's impossible, PHP code is compiled server-side, so all you return from a php compilation are static value, you must use AJAX to refresh the time value.

You could set the time with JS if you wish.