Javascript with fileReader for Image Upload _ javascript tips-js tutorial

What methods and events does FileReader support? I will not introduce them here. If you are interested, go to the w3c official website to see the introduction of FileReader. Here I will mainly introduce the common applications of FileReader, and fileReader. I will not explain the File API in detail here. We will use the File handle to read the File content. This is achieved through FileReader and through the FileReader interface, we can asynchronously load the file content into the memory and assign a js variable.

The Code is as follows:

Function getImgSrc (target, callback ){
If (window. FileReader ){
Var oPreviewImg = null, oFReader = new window. FileReader ();
OFReader. onload = function (oFREvent ){
OPreviewImg = new Image ();
Var type = target. files [0]. type. split ("/") [1];
Var src = oFREvent.tar get. result;
OPreviewImg. src = src;
If (typeof callback = "function "){
Callback (oPreviewImg, target, type, src );
}
Return oPreviewImg. src;
};
Return (function (){
Var aFiles = target. files;
If (aFiles. length = 0 ){
Return;
}
If (! IsImgType (aFiles [0]. type )){
Alert ("You must select a valid image file! ");
Return;
}
If (afile [0]. size> 1024*1024 ){
Target. value = "";
Alert ('Please upload image file size less than 1M .');
Return;
}
OFReader. readAsDataURL (aFiles [0]);
})();
}
If (navigator. appName = "Microsoft Internet Explorer "){
Return (function (){
Document. getElementById ("imagePreview"). filters. item ("DXImageTransform. Microsoft. AlphaImageLoader"). src = target. value;
})();
}
}

The above is the key code for javascript and fileReader to upload images. Do you like it?