JS lazy load to speed up the page opening sample code
- 2020-03-30 01:08:00
- OfStack
First, JS lazy loading
The code is as follows:
Second,JS loads last
Where JS needs to be inserted, insert the following code:
< SPAN id = L4EVER > LOADING... < / SPAN>
Sure, that LOADING... You can change it to your favorite small picture. It looks very AJAX.
Insert at the bottom of the page:
Third,JS loads last
Want to show the location of the AD
< Div id = "guangg1" > < / div>
The content of the AD you want to display
Determine whether the advertising location to be displayed exists
SetTimeout usage
The standard syntax for setTimeout is: setTimeout(expression, time (milliseconds)) with two parameters.
Note here that the first argument is a function call, assuming a function.
1. The function has no parameters:
The function alertV () {alert (" 000 "); }
When the first parameter is not quoted ("" or "), delay by one second:
SetTimeout (alertV, 1000);
When the first parameter is quoted, delay by one second:
SetTimeout (alertV "()", 1000);
2. Function has parameters:
Function alertV (event) {alert (" keyCode = "+ event. KeyCode); }
This should be set to:
SetTimeout (function () {alertV (event); }, 1000); Otherwise the parameter is not defined.
The code is as follows:
<script language="JavaScript" src="" id="my"></script>
<script language="JavaScript">
setTimeout("document.getElementById('my').src='include/... file ...php'; ",3000);//Delay 3 seconds
</script>
Second,JS loads last
Where JS needs to be inserted, insert the following code:
< SPAN id = L4EVER > LOADING... < / SPAN>
Sure, that LOADING... You can change it to your favorite small picture. It looks very AJAX.
Insert at the bottom of the page:
<SPAN class=spanclass id=AD_L4EVER>
your JS Here's the code !</SPAN>
<script>L4EVER.innerHTML=AD_L4EVER.innerHTML;AD_L4EVER.innerHTML="";</script>
Third,JS loads last
Want to show the location of the AD
< Div id = "guangg1" > < / div>
The content of the AD you want to display
<div id="ggad1" style="display:none">
<script language="javascript" src="/include/.......js"></script>
</div>
Determine whether the advertising location to be displayed exists
<script language="javascript">
function chkdiv(divid){
var chkid=document.getElementById(divid);
if(chkid != null)
{return true; }
else
{return false; }
} Finally, display ads
if (chkdiv('guangg1')) {
document.getElementById('guangg1').innerHTML= document.getElementById('ggad1').innerHTML;
document.getElementById('ggad1').innerHTML="";
}
</script>
SetTimeout usage
The standard syntax for setTimeout is: setTimeout(expression, time (milliseconds)) with two parameters.
Note here that the first argument is a function call, assuming a function.
1. The function has no parameters:
The function alertV () {alert (" 000 "); }
When the first parameter is not quoted ("" or "), delay by one second:
SetTimeout (alertV, 1000);
When the first parameter is quoted, delay by one second:
SetTimeout (alertV "()", 1000);
2. Function has parameters:
Function alertV (event) {alert (" keyCode = "+ event. KeyCode); }
This should be set to:
SetTimeout (function () {alertV (event); }, 1000); Otherwise the parameter is not defined.