very simple javascript image load question
Very new to javascript here folks, so forgive the newbie question.
I want to load a very simple and small image with javascript. Can I do an that is triggered by an onload?
Note: The reason 开发者_如何学JAVAfor this is I have a section of a website that requires javascript to work properly. I want to have a little green circle to show a user that they have javascript installed.
Pretty simple (no need to import a library):
<!-- somewhere in your document's <body> tag -->
<div id="divId">
</div>
<!-- in your document's <head> tag, or a separate .js file -->
<script>
// addLoadEvent function for executing JavaScript on page load
// adds the event in such a way that any previously added onload functions
// will be executed first.
function addLoadEvent(func) {
var oldonload = window.onload;
if (typeof window.onload != 'function') {
window.onload = func;
} else {
window.onload = function() {
if (oldonload) {
oldonload();
}
func();
}
}
}
addLoadEvent(function() {
document.getElementById('divId').innerHTML = "<img src='yourimage.gif' />"
// add more code here if necessary
});
</script>
This code assumes that you don't use JQuery.
var preloadedImage;
function PageIsLoaded(e)
{
preloadedImage = new Image();
img.src = 'pathToYourImage.jpg';
// preloading
img.onLoad = function () { displayImage() };
}
function displayImage()
{
// Assuming that this id refers to an IMG tag
var imgHolder = document.getElementById('imgHolder');
imgHolder = preloadedImage;
}
The most simple and easiest way to do this is using a javascript library, which utilizes load or ready functions. Example with jquery, launches, when document is ready :)
$(function () {
$('body').append('<img src="/img/js-is-working.jpg" />');
});
加载中,请稍侯......
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