Html 部分

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
    </head>

    <body>

        <input type="file" name="file" onchange="showPreview(this)" />
        <img id="portrait" src="" width="70" height="75">
    </body>

</html>

function showPreview(source) {
	var file = source.files[0];
	if (window.FileReader) {
		var fr = new FileReader();
		fr.onloadend = function(e) {
			document.getElementById("portrait").src = e.target.result;
		};
		fr.readAsDataURL(file);
	}
}