In HTML5 is there any way to make Filereader's readAsBinaryString() synchronous

Question

How to wait till onload event completes

function(){

var filedata=null;     
reader.onload=function(e){
filedata=e.target.result;
};
reader.readAsBinaryString(file);

//I need code to wait till onload event handler gets completed.
return filedata;
}

Answer 1

Typical solution to this is to separate your code so, that the part which uses the loaded data is in a separate function, which is then called from the event.

Pseudo-code'ish:

function load() {
    //load here
    reader.onload = function(e) {
        process(e.target.result);
    }
}

function process(result) {
    //finish working here
}

Answer 2

You can read synchronously using threads (Webworkers in Javascript).

http://www.w3.org/TR/FileAPI/#readingOnThreads