Convert Image to Binary Data or String in Javascript

问题:

I am working on uploading image file to TWITPIC using XMLHttp Request on a Chrome Extension . I need to send the image as payload. Is there a way to do this ? I found this link Convert an image into binary data in javascript But that works on image tags. i need a way to specify image file path and upload image to TWITPIC.

I came to know about FileReader API with HTML 5. Is there any way to work using that??. It should work on a local file.

Does Chrome Extension support FileReader API without running a localhost server ??

回答1:

I found the answer myself. Chrome Extensions does support FileReader API of HTML 5. So just the code below works simple.

  var reader = new FileReader();   reader.readAsDataURL(f); 

回答2:

You can use this to get the binary data of an image using XMLHTTPRequests, I used it recently for a similar purpose:

var dataToBinary = function(data){     var data_string = "";     for(var i=0; i<data.length; i++){         data_string += String.fromCharCode(data[i].charCodeAt(0) & 0xff);     }     return data_string; };  $.ajax("http://some.site.com/myImage.jpg", {     success: function(data){         binary = dataToBinary(data);         //or: 'binary = data', dataToBinary might not be needed     },     mimeType: "text/plain; charset=x-user-defined" }); 

And the binary data is stored in the binary variable.

文章来源: Convert Image to Binary Data or String in Javascript