Js checks whether the image is loaded and obtains the image width.

Web students often encounter situations where customers upload images to break through the webpage content area. The following describes how to use js to solve this problem, the specific idea is to process the width or height of the Image right after js judges that the Image on the client is downloaded. js processes the Image mainly by using the Image object in javascript, the onload event and onreadystatechange are used to determine whether to perform the operation.

(1) method 1, through the onload event, for example:

<Script type = "text/javascript"> var obj = new Image (); obj. src = "http://www.phpernote.com/uploadfiles/editor/201107240502201179.jpg"; obj. onload = function () {alert ('image width: '+ obj. width + '; the image height is:' + obj. height); document. getElementById ("mypic "). innnerHTML = " <div id = "mypic"> onloading ...... </Div>

(2) Method 2: onreadystatechange

<Script type = "text/javascript"> var obj = new Image (); obj. src = "http://www.phpernote.com/uploadfiles/editor/201107240502201179.jpg"; obj. onreadystatechange = function () {if (this. readyState = "complete") {alert ('image width: '+ obj. width + '; the image height is:' + obj. height); document. getElementById ("mypic "). innnerHTML = " <div id = "mypic"> onloading ...... </Div>

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