function addLoadEvent(func) {
	var oldonload = window.onload;
	if (typeof window.onload != "function") {
		window.onload = func;
	}
	else {
		window.onload = function() {
			if (oldonload) {
				oldonload();
			}
			func();
		};
	}
}

String.prototype.strReverse = function() {
	var newstring = "";
	for (var s=0; s < this.length; s++) {
		newstring = this.charAt(s) + newstring;
	}
	return newstring;
	//strOrig = ' texttotrim ';
	//strReversed = strOrig.revstring();
};

function chkPass(pwd) {
	var oScorebar = document.getElementById("scorebar");
	var oScore = document.getElementById("score");
	var oComplexity = document.getElementById("complexity");
	var nScore = 0;
	var nLength = 0;
	var nAlphaUC = 0;
	var nAlphaLC = 0;
	var nNumber = 0;
	var nSymbol = 0;
	var nMidChar = 0;
	var nRequirements = 0;
	var nRepChar = 0;
	var nConsecAlphaUC = 0;
	var nConsecAlphaLC = 0;
	var nConsecNumber = 0;
	var nConsecSymbol = 0;
	var nConsecCharType = 0;
	var nSeqAlpha = 0;
	var nSeqNumber = 0;
	var nSeqChar = 0;
	var nReqChar = 0;
	var nReqCharType = 3;
	var nMultLength = 4;
	var nMultAlphaUC = 3;
	var nMultAlphaLC = 3;
	var nMultNumber = 4;
	var nMultSymbol = 6;
	var nMultMidChar = 2;
	var nMultRequirements = 2;
	var nMultRepChar = 1;
	var nMultConsecAlphaUC = 2;
	var nMultConsecAlphaLC = 2;
	var nMultConsecNumber = 2;
	var nMultConsecSymbol = 1;
	var nMultConsecCharType = 0;
	var nMultSeqAlpha = 3;
	var nMultSeqNumber = 3;
	var nTmpAlphaUC = "";
	var nTmpAlphaLC = "";
	var nTmpNumber = "";
	var nTmpSymbol = "";
	var sAlphas = "abcdefghijklmnopqrstuvwxyz";
	var sNumerics = "01234567890";
	var sComplexity = "Quá ngắn";
	var sStandards = "Below";
	var nMinPwdLen = 4;
	if (document.all) { var nd = 0; } else { var nd = 1; }	
	if (pwd.length >= nMinPwdLen) {
		nScore = parseInt(pwd.length * nMultLength);
		nLength = pwd.length;
		var arrPwd = pwd.replace (/\s+/g,"").split(/\s*/);
		var arrPwdLen = arrPwd.length;
		
		/* Loop through password to check for Symbol, Numeric, Lowercase and Uppercase pattern matches */
		for (var a=0; a < arrPwdLen; a++) {
			if (arrPwd[a].match(new RegExp(/[A-Z]/g))) {
				if (nTmpAlphaUC !== "") { if ((nTmpAlphaUC + 1) == a) { nConsecAlphaUC++; nConsecCharType++; } }
				nTmpAlphaUC = a;
				nAlphaUC++;
			}
			else if (arrPwd[a].match(new RegExp(/[a-z]/g))) { 
				if (nTmpAlphaLC !== "") { if ((nTmpAlphaLC + 1) == a) { nConsecAlphaLC++; nConsecCharType++; } }
				nTmpAlphaLC = a;
				nAlphaLC++;
			}
			else if (arrPwd[a].match(new RegExp(/[0-9]/g))) { 
				if (a > 0 && a < (arrPwdLen - 1)) { nMidChar++; }
				if (nTmpNumber !== "") { if ((nTmpNumber + 1) == a) { nConsecNumber++; nConsecCharType++; } }
				nTmpNumber = a;
				nNumber++;
			}
			else if (arrPwd[a].match(new RegExp(/[^a-zA-Z0-9_]/g))) { 
				if (a > 0 && a < (arrPwdLen - 1)) { nMidChar++; }
				if (nTmpSymbol !== "") { if ((nTmpSymbol + 1) == a) { nConsecSymbol++; nConsecCharType++; } }
				nTmpSymbol = a;
				nSymbol++;
			}
			/* Internal loop through password to check for repeated characters */
			for (var b=0; b < arrPwdLen; b++) {
				if (arrPwd[a].toLowerCase() == arrPwd[b].toLowerCase() && a != b) { nRepChar++; }
			}
		}
		
		/* Check for sequential alpha string patterns (forward and reverse) */
		for (var s=0; s < 23; s++) {
			var sFwd = sAlphas.substring(s,parseInt(s+3));
			var sRev = sFwd.strReverse();
			if (pwd.toLowerCase().indexOf(sFwd) != -1 || pwd.toLowerCase().indexOf(sRev) != -1) { nSeqAlpha++; nSeqChar++;}
		}
		
		/* Check for sequential numeric string patterns (forward and reverse) */
		for (var s=0; s < 8; s++) {
			var sFwd = sNumerics.substring(s,parseInt(s+3));
			var sRev = sFwd.strReverse();
			if (pwd.toLowerCase().indexOf(sFwd) != -1 || pwd.toLowerCase().indexOf(sRev) != -1) { nSeqNumber++; nSeqChar++;}
		}
		
	/* Modify overall score value based on usage vs requirements */

		/* General point assignment */
		if (nAlphaUC > 0 && nAlphaUC < nLength) {	
			nScore = parseInt(nScore + ((nLength - nAlphaUC) * 2));
		}
		if (nAlphaLC > 0 && nAlphaLC < nLength) {	
			nScore = parseInt(nScore + ((nLength - nAlphaLC) * 2)); 
		}
		if (nNumber > 0 && nNumber < nLength) {	
			nScore = parseInt(nScore + (nNumber * nMultNumber));
		}
		if (nSymbol > 0) {	
			nScore = parseInt(nScore + (nSymbol * nMultSymbol));
		}
		if (nMidChar > 0) {	
			nScore = parseInt(nScore + (nMidChar * nMultMidChar));
		}		
		/* Point deductions for poor practices */
		if ((nAlphaLC > 0 || nAlphaUC > 0) && nSymbol === 0 && nNumber === 0) {  // Only Letters
			nScore = parseInt(nScore - nLength/2);
		}
		if (nAlphaLC === 0 && nAlphaUC === 0 && nSymbol === 0 && nNumber > 0) {  // Only Numbers
			nScore = parseInt(nScore - nLength/2); 		}
		
		
		/* Determine complexity based on overall score */
		if (nScore > 100) { nScore = 100; } else if (nScore < 0) { nScore = 0; }
		if (nScore >= 0 && nScore < 20) { sComplexity = "Rất đơn giản"; }
		else if (nScore >= 20 && nScore < 40) { sComplexity = "Đơn giản"; }
		else if (nScore >= 40 && nScore < 60) { sComplexity = "Tốt"; }
		else if (nScore >= 60 && nScore < 80) { sComplexity = "Khó"; }
		else if (nScore >= 80 && nScore <= 100) { sComplexity = "Rất khó"; }
		
		/* Display updated score criteria to client */
		oScorebar.style.backgroundPosition = "-" + parseInt(nScore * 4) + "px";
		oScore.innerHTML = nScore + "%";
		oComplexity.innerHTML = sComplexity;
	}
	else
	{
		if(pwd)
		{
			nScore = 0;
			oScore.innerHTML = nScore + "%";
			oComplexity.innerHTML = sComplexity;
		}
		else
		{
			/* Display default score criteria to client */
			initPwdChk();
			oScore.innerHTML = nScore + "%";
			oComplexity.innerHTML = sComplexity;
		}
	}
	return nScore;
}

function togPwdMask(oMask,_1,_2) {
	var oPwd = document.getElementById(_1);
	var oTxt = document.getElementById(_2);	
	if (oMask.checked) {
		oPwd.value = oTxt.value;
		oPwd.className = ""; 
		oTxt.className = "hide"; 
	} 
	else { 
		oTxt.value = oPwd.value;
		oPwd.className = "hide"; 
		oTxt.className = "";
	}
}

addLoadEvent(function() { chkPass(document.getElementById("passwordPwd").value); });

function initPwdChk(restart) {
	/* Reset all form values to their default */
	document.getElementById("passwordPwd").value = "";
	document.getElementById("passwordTxt").value = "";
	document.getElementById("scorebar").style.backgroundPosition = "0";
	if (restart) {
		document.getElementById("passwordPwd").className = "";
		document.getElementById("passwordTxt").className = "hide";
		document.getElementById("mask").checked = true;
	}
}

function getRandomNum(lbound, ubound)
{
	return (Math.floor(Math.random() * (ubound - lbound)) + lbound);
}
function getRandomChar(number, lower, upper, other, extra) 
{
	var numberChars = "0123456789";
	var lowerChars = "abcdefghijklmnopqrstuvwxyz";
	var upperChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
	var otherChars = "`~!@#$%^&*()-_=+[{]}\\|;:'\",<.>/?";
	var charSet = extra;
	if (number == true)
	charSet += numberChars;
	if (lower == true)
	charSet += lowerChars;
	if (upper == true)
	charSet += upperChars;
	if (other == true)
	charSet += otherChars;
	return charSet.charAt(getRandomNum(0, charSet.length));
}

function getPassword(length)
{
	var rc = "";
	if (length > 0)
		rc = rc + getRandomChar(1,true, true, true);
	for (var idx = 1; idx < length; ++idx)
	{
		rc = rc + getRandomChar(length-1, true, true, true);
	}
	return rc;
}