javascript Preview an image before it is uploaded

function readURL(input) {

    if (input.files && input.files[0]) {
        var reader = new FileReader();

        reader.onload = function (e) {
            $('#blah').attr('src', e.target.result);
        }

        reader.readAsDataURL(input.files[0]);
    }
}

$("#imgInp").change(function(){
    readURL(this);
});

and the associated HTML:

<form id="form1" runat="server">
    <input type='file' id="imgInp" />
    <img id="blah" src="#" alt="your image" />
</form>

I want to be able to preview a file (image) before it is uploaded. The preview action should be executed all in the browser without using Ajax to upload the image. How can I do this?

Source: javascript – Preview an image before it is uploaded – Stack Overflow