JavaScript-based proportional scaling of webpage images-Javascript tutorial

JavaScript: JavaScript enables proportional scaling of webpage images. For the Javascript tutorial, refer to some code and write a script for Image Scaling. You can click to zoom in and use the mouse wheel to scale freely. // scale the image proportionally. You can enter a parameter to set the initial size.
Function resizeimg (ImgD, iwidth, iheight ){
Var image = new Image ();
Image. src = ImgD. src;
If (image. width> 0 & image. height> 0 ){
If (image. width/image. height> = iwidth/iheight ){
If (image. width> iwidth ){
ImgD. width = iwidth;
ImgD. height = (image. height * iwidth)/image. width;
} Else {
ImgD. width = image. width;
ImgD. height = image. height;
}
ImgD. alt = image. width + "×" + image. height;
}
Else {
If (image. height> iheight ){
ImgD. height = iheight;
ImgD. width = (image. width * iheight)/image. height;
} Else {
ImgD. width = image. width;
ImgD. height = image. height;
}
ImgD. alt = image. width + "×" + image. height;
}
ImgD. style. cursor = "pointer"; // change the mouse pointer
ImgD. onclick = function () {window. open (this. src);} // click to open the large image.
If (navigator. userAgent. toLowerCase (). indexOf ("ie")>-1) {// judge the browser. if it is IE
ImgD. title = "Please use the scroll wheel to zoom in the image. Click the image to open it in a new window ";
ImgD. onmousewheel = function img_zoom () // scroll wheel Scaling
{
Var zoom = parseInt (this. style. zoom, 10) || 100;
Zoom + = event. wheelDelta/12;
If (zoom> 0) this. style. zoom = zoom + "% ";
Return false;
}
} Else {// if it is not IE
ImgD. title = "click an image to open it in a new window ";
}
}
} The specific implementation code is as follows: it may be quite necessary. If you have better code, please kindly advise!