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  1. #1
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    Detect the Image Size (Dimensions) from an Image URL and Related for eBay

    QUESTION 1:

    Hello. I would like to know if this is possible with Javascript, and if yes, if someone can please provide me with the code or point me in the right direction.

    Let me start of by saying that this is for an eBay listing. I know that they accept basic / limited javascript and if what I am asking is possible, I hope that it can work on eBay listings.

    I would like to know if it's possible to determine the dimensions of an image with Javascript from an Image url, and to then resize it or not based on the the size of the image.

    So, let's say this is the URL: www.adomainname.com/image.jpg

    and let's say that image is 1400 px x 1400 px. I would first like the javascript code to detect that size. I also would like the maximum dimension for any side of the image to be 600 px. If both sides of the image are over 600 px, for both sides to be reduced proportionally to 600 px or lower. If any one side of the image is larger than 600 px, the image is to be resized to 600 px or lower. If both sides are under 600 px, the image is to not be reduced. It would also be nice if it can detect whether the image is portion or landscape based on I guess the larger side, because an image at 600 px in height might be too big, but in width might be o.k.

    So, in this example (the 1400 px by 1400 px), the image is to be resized to 600 px x 600 px.

    For an image that's 300 px x 500 px, it should remain as such.

    For an image that's 400 px x 700 px, it should be resized to 400 / (700 / 600) px by 600 px, which is approximately 343 px x 600 px.

    I have looked a bit into this and I see things being mentioned about the image being loaded first completely on the screen, or about using server side language like PHP, and so on, but like I said, keep in mind that this is for eBay, and so I am limited.

    Note: The part that I am most interested in is in being able to detect the size / dimensions of the image.

    QUESTION 2:

    On a side note, does anyone know if it's possible to have a Javascript enlarging function for images, in which when one clicks on an image, it is enlarged, but either in a popup window that's smaller than the one behind it, and possibly centered, or by making the background go dark and then bringing up the enlarged image (is the latter done with Javascript; I have seen this effect for a while now and have always wondered.)

  2. #2
    SitePoint Zealot Amit Yaron's Avatar
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    You can detect an "img" elements height and width using its HTML DOM properties "height: and "width". I recommend that you retrieve those attributes asynchronously using the event attribute "onload". e.g.
    Code:
    <img src="image source" onload="alert(this.height + "," + this.width);" />


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