i have image box and some value coming on that image-box, what i want that,get that value. could it be possible to convert image in to string or character or any other way to get that value.

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<img id="imgid" name="img" src="CaptchaSecurityImages.php?width=100&height=40&characters=5" />

i want this image value convert into string of in character in either by java script or by php.
or any alternate way to get the value of a image box.

if possible than pls revert ASAP.