Question
I am trying to load images using webworker api. I have large images in my html page its takes 5 mins to load all images therefore i am using webworker to load images.
here is technique..
I am keeping src attribute of all img tag empty in html page.
All images have unique id for each img e.g id = events_all_1_01 meaning image src will be "pictures/keywords/events/all/1/01.jpg". i.e last part events/all/1/01.jpg is id.
Main.html file
https://stackoverflow.com/questions/23268322
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Russian <body>
<script src="js/modernizr.custom.js"></script>
<script language="javascript">
window.onload = function(){
if (Modernizr.webworkers) {
var worker = new Worker('js/webworker/test_ww_23_04.js');
worker.onmessage = function(event) {
var url = event.data.replace(/_/g, "/");
var image_src = "pictures/keywords/"+url+".jpg";
var img = new Image();
img.src = image_src;
img.onload = function(){
// do stuff when your image is loaded
document.getElementById(event.data).src = image_src;
}
};
worker.onerror = function(e) {
alert('Error: Line ' + e.lineno + ' in ' + e.filename + ': ' + e.message);
};
var img_container = document.getElementById("wrapper");
var image_array = img_container.getElementsByTagName('img');
for(var i=0;i<image_array.length;i++){
var img_id = image_array[i].id;
console.log(img_id); // http://jsfiddle.net/5vyseob7/
postMessage(img_id); // http://jsfiddle.net/k04t6760/ here i am passing id one by one to webworker..
}
} // end of if condition
} // end of window.onload()
</script>
<div id="wrapper" style="height: 500px;width: 200px;overflow-y: auto;border: 1px solid gray;">
<div id="pictures1">
<div class="effect-1">
<div><img src="" id="events_all_1_01" width="150" height="100"></div>
<div><img src="" id="events_all_1_02" width="150" height="100"></div>
<div><img src="" id="events_all_1_03" width="150" height="100"></div>
<div><img src="" id="events_all_1_04" width="150" height="100"></div>
</div>
<hr/>
<div class="effect-2">
<div><img src="" id="events_all_2_01" width="150" height="100"></div>
<div><img src="" id="events_all_2_02" width="150" height="100"></div>
<div><img src="" id="events_all_2_03" width="150" height="100"></div>
<div><img src="" id="events_all_2_04" width="150" height="100"></div>
</div>
<hr/>
<div class="effect-3">
<div><img src="" id="events_all_3_01" width="150" height="100"></div>
<div><img src="" id="events_all_3_02" width="150" height="100"></div>
<div><img src="" id="events_all_3_03" width="150" height="100"></div>
<div><img src="" id="events_all_3_04" width="150" height="100"></div>
</div>
<hr/>
<div class="effect-4">
<div><img src="" id="events_all_4_01" width="150" height="100"></div>
<div><img src="" id="events_all_4_02" width="150" height="100"></div>
<div><img src="" id="events_all_4_03" width="150" height="100"></div>
<div><img src="" id="events_all_4_04" width="150" height="100"></div>
</div>
</div>
</div>
</body>
webworker code.
//var src = 'pictures/keywords/events/all/1/01.jpg';
//var id = src.substring(src.substring(0,18).length).split('.')[0].replace(/\//g, "_"); // Creating id here......events_all_1_01
//var fst = id.substring(0, id.lastIndexOf("_")+1); // get first part.... events_all_1
//var lst = parseInt(id.substr(id.lastIndexOf("_")+1)); // get last part i.e imagename ..01,02,03 etc....... and convert it to int
function LoadImages(currID) {
setTimeout(function() {
postMessage(currID);
}, 100);
}
self.onmessage = function(event) {
var currID = event.data;
LoadImages(currID);
};
I am getting following error :
Uncaught SyntaxError: Failed to execute 'postMessage' on 'Window': Invalid target origin '' in a call to 'postMessage'.
La solution
Typo error:
...
worker.onmessage = function(event) {
var url = e.data.replace(/_/g, "/");
e is not defined ... you probably meant function(e) or event.data.replace
UPDATE
Window don't have the postMessage method ... you need to use the worker method worker.postMessage
