window.print very slow . Alert comes before print

Question

In the below code second alert comes before the first print pop page. Search results says window.print is a OS functionality and it does not have return value.

Second alert should come only after the print popup. Kindly help

<script>
    function myFunction() {
        for(i=0;i<6;i++){
            alert('Printing Copy:'+i);
            window.print();
        }
    }
</script>

Also, know that in your case `alert()` will pop only once. Same for `print()` — Roko C. Buljan, Jul 29 '14 at 05:15
what browser you are use? I have not this issue with chrome, both function calls are blocking... — vp_arth, Jul 29 '14 at 05:22
I ran this snippet in my chrome console and every alert is displayed before the corresponding print popup (i.e. `alert0` then print model then `alert1` then print model... etc). what browser are you using? — RossBille, Jul 29 '14 at 05:27
"second alert comes before the first print pop page". What does the _second alert_ say? — sampathsris, Jul 29 '14 at 06:05
Are your users really that inept to change to number of prints to 6 in the dialog? — Kijewski, Jul 29 '14 at 06:19

sampathsris · Answer 1 · 2019-06-28T01:34:55.893

window.print is an asynchronous function. "Asynchronous" means that the execution will immediately return to the calling function, and whatever that is expected to be done by the function will happen in another time.

What happens in your case is this: You are looping several times, and each time you are alerting the user that you are going to print the document, and then you call print. However, the print call will immediately return, and your loop will get to the second iteration before it pops up the print dialog for the first iteration.

As a remedy, you can use onbeforeprint to alert the user that you are going to print the document.

function myFunction() {
    for(i=0; i<6; i++){
        window.onbeforeprint = function(){
            alert("Printing copy:" + i);
        }

        window.print();
    }
}

Note: If you do not understand how this code works, you may want to search and learn a bit about "JavaScript closures", "callbacks", and "asynchronous functions".

window.print very slow . Alert comes before print

1 Answers1