Javascript Determine Image Size Example Analysis_javascript Skills

Usually we judge the size of js images by using the images object, and then using attr to get the image address and then judging . Let’s take a look at some examples.
Easiest way:

Copy code The code is as follows:

var img=new Image();
img .src=$('#tlogo').attr('src');
if(img.width > '240'){
$('#tlogo').attr('width', '240');
}

In the above example, if the page has not been loaded, js will not be able to obtain the image size. For this, we can first determine whether the loading is complete and then determine the image size.

Copy code The code is as follows:

Or use jquery:

Copy code The code is as follows:

$("#imageId").load(function( ){
alert("Loading completed!");
});

Now we can optimize the code

Copy code The code is as follows:

$("#tlogo").load(function( ){
var img=new Image();
img.src=$('#tlogo').attr('src');
if(img.width > '240'){
        $('#tlogo').attr('width','240');
}
});

Note here: #tlogo is an ID added to your picture address. This is required.