Call JavaScript in SharePoint Page.



If you ever want to load your script code at the correct moment in a share-point page.

Run javascript at the end of page load , right at the correct moment.

<script>

document.addEventListener("DOMContentLoaded", theDomHasLoaded, false);

window.addEventListener("load", pageFullyLoaded, false);

function theDomHasLoaded(e) {

    // do something

}

function pageFullyLoaded(e) {

    // do something again

}

</script>

Refer to this link