window.onload与document.onload

$(document).ready(function() { /* code here */ });
$(function() { /* code here */ });

<script language="javascript">
window.tdiff = []; fred = function(a,b){return a-b;};
window.document.onload = function(e){ 
    console.log("document.onload", e, Date.now() ,window.tdiff,  
    (window.tdiff[0] = Date.now()) && window.tdiff.reduce(fred) ); 
}
window.onload = function(e){ 
    console.log("window.onload", e, Date.now() ,window.tdiff, 
    (window.tdiff[1] = Date.now()) && window.tdiff.reduce(fred) ); 
}
</script>

<script type="text/javascript">
  document.addEventListener("DOMContentLoaded", function(event) {
      // - Code to execute when all DOM content is loaded. 
      // - including fonts, images, etc.
  });
</script>

window.addEventListener('load', function() {
    console.log('All assets are loaded')
})

$(window).on('load', function() {
    console.log('All assets are loaded')
})

window.addEventListener('DOMContentLoaded', function() {
  console.log('window - DOMContentLoaded - capture'); // 1st
}, true);
document.addEventListener('DOMContentLoaded', function() {
  console.log('document - DOMContentLoaded - capture'); // 2nd
}, true);
document.addEventListener('DOMContentLoaded', function() {
  console.log('document - DOMContentLoaded - bubble'); // 2nd
});
window.addEventListener('DOMContentLoaded', function() {
  console.log('window - DOMContentLoaded - bubble'); // 3rd
});

window.addEventListener('load', function() {
  console.log('window - load - capture'); // 4th
}, true);
document.addEventListener('load', function(e) {
  /* Filter out load events not related to the document */
  if(['style','script'].indexOf(e.target.tagName.toLowerCase()) < 0)
    console.log('document - load - capture'); // DOES NOT HAPPEN
}, true);
document.addEventListener('load', function() {
  console.log('document - load - bubble'); // DOES NOT HAPPEN
});
window.addEventListener('load', function() {
  console.log('window - load - bubble'); // 4th
});

window.onload = function() {
  console.log('window - onload'); // 4th
};
document.onload = function() {
  console.log('document - onload'); // DOES NOT HAPPEN
};

        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />



        <script language="javascript">

            function bodyOnloadHandler() {
                console.log("body onload");
            }

            window.onload = function(e) {
                console.log("window loaded");
            };
        </script>




        Page contents go here.