var minpwlength = 4;
	var fairpwlength = 7;
	
	var STRENGTH_SHORT = 0;  // less than minpwlength 
	var STRENGTH_WEAK = 1;  // less than fairpwlength
	var STRENGTH_FAIR = 2;  // fairpwlength or over, no numbers
	var STRENGTH_STRONG = 3; // fairpwlength or over with at least one number
	
	img0 = new Image(); 
	img1 = new Image();
	img2 = new Image();
	img3 = new Image();
	
	img0.src = '/images/pwdcheck/tooshort.jpg';
	img1.src = '/images/pwdcheck/fair.jpg';
	img2.src = '/images/pwdcheck/medium.jpg';
	img3.src = '/images/pwdcheck/strong.jpg';
	
	var strengthlevel = 0;
	
	var strengthimages = Array( img0.src,
								img1.src,
								img2.src,
								img3.src );
	
	function updatestrength( pw ) {
	
		if(istoosmall(pw)) {
	
			strengthlevel = STRENGTH_SHORT;
	
		}
		else if( !isfair( pw ) ) { 
	
			strengthlevel = STRENGTH_WEAK;
	
		}	
		else if( hasnum( pw ) ) {
	
			strengthlevel = STRENGTH_STRONG;
	
		}
		else {
	
			strengthlevel = STRENGTH_FAIR;
	
		}
	
		document.getElementById( 'strength' ).src = strengthimages[ strengthlevel ];
	
	}
	
	function isfair( pw ) {
	
		if( pw.length < fairpwlength ) {
	
			return false;
	
		}
		else { 
	
			return true;
	
		}
	
	}
	
	function istoosmall( pw ) {
	
		if( pw.length < minpwlength ) {
	
			return true;
	
		}
		else {
	
			return false;

		}
	
	}
	
	function hasnum( pw ) {
	
		var hasnum = false;
	
		for( var counter = 0; counter < pw.length; counter ++ ) {
	
			if( !isNaN( pw.charAt( counter ) ) ) {
	
				hasnum = true;
	
			}
	
		}
	
	
		return hasnum;
	
	}