Is there a function to find the amount bytes currently loaded from a file with XMLHtttpRequest?

I'm trying to write a loading screen using the file size and the amount of bytes loaded from the file. I'm able to get the file size with the XmlHttpRequest.getResponseHeader ("Content-Length") but I want to get the size of the file loaded so far in order for me to write a function that will update a 开发者_Go百科<div> on my my webpage to show the percentage loaded so far.

Is there a function similar to .getResponseHeader("Content-Length") that will return the current amount of the file loaded instead of the total file size?

Cheers,

Dez

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XMLHttRequest.responseText.length will probably be correct.

You will need to make sure you get the value when onreadystatechange == 3 to get the amount of bytes loaded so far. you can then use that data to calculate your loading screen. If you use it when onreadystatechange == 4 it will give you the amount of bytes of the whole file and not the bytes sent so far.