问题:

How to get real image width & height (cross browser) by JavaScript function ?

回答1:

First of all, you have a greater chance of getting your question answered if you'd just ask it in a more polite way, and supplying as much relevant information as possible.

Anyway...

For as far as I know, you can use the .width property across pretty much all browsers:

function getDimensions(id) {
    var element = document.getElementById(id);
    if (element && element.tagName.toLowerCase() == 'img') {
        return {
            width: element.width,
            height: element.height
        };
    }
}

<img id="myimage" src="foo.jpg" alt="" />

// using the function on the above image:
var dims = getDimensions('myimage');
alert(dims.width); --> shows width
alert(dims.height); --> shows height

回答2:

var realWidth = $("#image").attr("naturalWidth");
var realHeight = $("#image").attr("naturalHeight");

回答3:

Yay, Google!

There's a few ways to do this depending on exactly what you need (which you have unhelpfully omitted to include). Probably the simplest in a general sense is to get a reference to the Image object and inspect the width and height properties.