I've got the following code in my Javascript:

var reader = new FileReader();

reader.onloadend = function () {

    alert(reader.result);

};

This shows me the following data:

 data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAAAAABX3VL4AAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3gYSDCUgSze0AAAAAA5JREFUCNdjrGJgYmAAAAJ0AH4SDHVIAAAAAElFTkSuQmCC

The thing is that I only want the part after the comma. I tried getting it from reader.result.value, reader.result.valueOf() and some other combinations, but can't find the correct one to JUST get the base64 string starting from after the comma. So a second idea is to simply strip off the comma and all that is before that, but I'm kind of unsure how to do that.

Would anybody have any idea how to get this done? All tips are welcome!