JavaScript: Password Validation using regular expressions and HTML5

<script type="text/javascript"> 
function checkForm(form) 
{ 
if(form.username.value == "") 
{ 
alert("Error: Username cannot be blank!"); 
form.username.focus(); 
return 
false; 
} 
re = /^\w+$/; 
if(!re.test(form.username.value)) 
{ 
alert("Error: Username must contain only letters, numbers and underscores!"); form.username.focus(); 
return false; 
} 
if(form.pwd1.value != "" && form.pwd1.value == form.pwd2.value) 
{ 
if(form.pwd1.value.length < 6) 
{ 
alert("Error: Password must contain at least six characters!"); form.pwd1.focus(); 
return false; 
} 
if(form.pwd1.value == form.username.value) 
{ 
alert("Error: Password must be different from Username!"); 
form.pwd1.focus(); 
return false; 
} 
re = /[0-9]/; if(!re.test(form.pwd1.value)) 
{ 
alert("Error: password must contain at least one number (0-9)!"); form.pwd1.focus(); return false; 
} 
re = /[a-z]/; 
if(!re.test(form.pwd1.value)) 
{ 
alert("Error: password must contain at least one lowercase letter (a-z)!"); form.pwd1.focus(); 
return false; 
} 
re = /[A-Z]/; 
if(!re.test(form.pwd1.value)) 
{ 
alert("Error: password must contain at least one uppercase letter (A-Z)!"); form.pwd1.focus(); 
return false; 
} 
} 
else 
{ 
alert("Error: Please check that you've entered and confirmed your password!"); form.pwd1.focus(); 
return false; 
} 
alert("You entered a valid password: " + form.pwd1.value); 
return true; 
} 
</script> 
<form ... onsubmit="return checkForm(this);"> 
<p>Username: <input type="text" name="username"></p> 
<p>Password: <input type="password" name="pwd1"></p> 
<p>Confirm Password: <input type="password" name="pwd2"></p> 
<p><input type="submit"></p> 

</form>

Sample HTML and JavaScript code

<script type="text/javascript"> 
 function checkPassword(str) 
{ 
var re = /^(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{6,}$/; 
return re.test(str); 
} 
function checkForm(form) 
{ 
if(form.username.value == "") 
{ 
alert("Error: Username cannot be blank!"); 
form.username.focus(); 
return false; 
} 
re = /^\w+$/; if(!re.test(form.username.value)) 
{ 
alert("Error: Username must contain only letters, numbers and underscores!"); form.username.focus(); 
return false; 
} 
if(form.pwd1.value != "" && form.pwd1.value == form.pwd2.value) 
{ 
if(!checkPassword(form.pwd1.value)) 
{ 
alert("The password you have entered is not valid!"); 
form.pwd1.focus(); return false; 
} 
} 
else 
{ 
alert("Error: Please check that you've entered and confirmed your password!"); form.pwd1.focus(); 
return false; 
} 
return true; 
} 
</script> 
<form method="POST" action="..." onsubmit="return checkForm(this);"> 
<p>Username: <input type="text" name="username"></p> 
<p>Password: <input type="password" name="pwd1"></p> 
<p>Confirm Password: <input type="password" name="pwd2"></p> 
<p><input type="submit"></p> 
</form>

Aptitude Questions with answer

1.If 2x-y=4 then 6x-3y=?
(a)15
(b)12
(c)18
(d)10
Ans. (b)

2.If x=y=2z and xyz=256 then what is the value of x?
(a)12
(b)8
(c)16
(d)6
Ans. (b)

3. (1/10)¹⁸ - (1/10)²⁰ = ?
(a) 99/10²⁰
(b) 99/10
(c) 0.9
(d) none of these
Ans. (a)

4.Pipe A can fill in 20 minutes and Pipe B in 30 mins and Pipe C can empty the same in 40 mins.If all of them work together, find the time taken to fill the tank
(a) 17 1/7 mins
(b) 20 mins
(c) 8 mins
(d) none of these
Ans. (a)

5. Thirty men take 20 days to complete a job working 9 hours a day.How many hour a day should 40 men work to complete the job?
(a) 8 hrs
(b) 7 1/2 hrs
(c) 7 hrs
(d) 9 hrs
Ans. (b)


6. Find the smallest number in a GP whose sum is 38 and product 1728
(a) 12
(b) 20
(c) 8
(d) none of these
Ans. (c)

7. A boat travels 20 kms upstream in 6 hrs and 18 kms downstream in 4 hrs.Find the speed of the boat in still water and the speed of the water current?
(a) 1/2 kmph
(b) 7/12 kmph
(c) 5 kmph
(d) none of these
Ans. (b)

8. A goat is tied to one corner of a square plot of side 12m by a rope 7m long.Find the area it can graze?
(a) 38.5 sq.m
(b) 155 sq.m
(c) 144 sq.m
(d) 19.25 sq.m
Ans. (a)

9. Mr. Shah decided to walk down the escalator of a tube station. He found   that if he walks down 26 steps, he requires 30 seconds to reach the bottom. However, if he steps down 34 stairs he would only require 18 seconds to get to the bottom. If the time is measured from the moment the top step begins   to descend to the time he steps off the last step at the bottom, find out the height of the stair way in steps?
Ans.46 steps.

10. The average age of 10 members of a committee is the same as it was 4 years ago, because an old member has been replaced by a young member. Find how much younger is the new member ?
Ans.40 years.

11. Three containers A, B and C have volumes a, b, and c respectively; and container A is full of water while the other two are empty. If from container A water is poured into container B which becomes 1/3 full, and into container C which becomes 1/2 full, how much water is left in container A?

12. ABCE is an isosceles trapezoid and ACDE is a rectangle. AB = 10 and EC = 20. What is the length of AE?
Ans. AE = 10.

13. In the given figure, PA and PB are tangents to the circle at A and B respectively and   the chord BC is parallel to tangent PA. If AC = 6 cm, and length of the tangent AP   is 9 cm, then what is the length of the chord BC?
Ans. BC = 4 cm.

15 Three cards are drawn at random from an ordinary pack of cards. Find the probability that they will consist of a king, a queen and an ace.
Ans. 64/2210.

16. A number of cats got together and decided to kill between them 999919   mice. Every cat killed an equal number of mice. Each cat killed more mice   than there were cats. How many cats do you think there were ?
Ans. 991.

17. If Log2 x - 5 Log x + 6 = 0, then what would the value / values of x be?
Ans. x = e2 or e3.

18. The square of a two digit number is divided by half the number. After   36 is added to the quotient, this sum is then divided by 2. The digits of the resulting number are the same as those in the original number, but they   are in reverse order. The ten's place of the original number is equal to twice   the difference between its digits. What is the number?
Ans. 46

19.Can you tender a one rupee note in such a manner that there shall be   total 50 coins but none of them would be 2 paise coins.?
Ans. 45 one paisa coins, 2 five paise coins, 2 ten paise coins, and 1 twenty-five paise coins.

20.A monkey starts climbing up a tree 20ft. tall. Each hour, it hops 3ft. and slips back 2ft. How much time would it take the monkey to reach the top?
Ans.18 hours.

21. What is the missing number in this series?   8 2 14 6 11 ? 14 6 18 12
Ans. 9

22. A certain type of mixture is prepared by mixing brand A at Rs.9 a kg. with brand B at Rs.4 a kg. If the mixture is worth Rs.7 a kg., how many   kgs. of brand A are needed to make 40kgs. of the mixture?
Ans. Brand A needed is 24kgs.

23. A wizard named Nepo says "I am only three times my son's age. My father   is 40 years more than twice my age. Together the three of us are a mere 1240   years old." How old is Nepo?
Ans. 360 years old.

24. One dog tells the other that there are two dogs in front of me. The other one also shouts that he too had two behind him. How many are they?
Ans. Three.

25. A man ate 100 bananas in five days, each day eating 6 more than the previous day. How many bananas did he eat on the first day?
Ans. Eight.


26. If it takes five minutes to boil one egg, how long will it take to boil four eggs?
Ans. Five minutes.

27. The minute hand of a clock overtakes the hour hand at intervals of 64   minutes of correct time. How much a day does the clock gain or lose?
Ans. 32 8/11 minutes.

28. Solve for x and y:   1/x - 1/y = 1/3, 1/x2 + 1/y2 = 5/9.
Ans. x = 3/2 or -3 and y = 3 or -3/2.

29. Daal is now being sold at Rs. 20 a kg. During last month its rate was Rs. 16 per kg. By how much percent should a family reduce its consumption so   as to keep the expenditure fixed?
Ans. 20 %.

30. Find the least value of 3x + 4y if x2y3 = 6.
Ans. 10.

31. Can you find out what day of the week was January 12, 1979?
Ans. Friday.

32. A garrison of 3300 men has provisions for 32 days, when given at a rate of 850 grams per head. At the end of 7 days a reinforcement arrives and it was found that now the provisions will last 8 days less, when given at the rate of 825 grams per head. How, many more men can it feed?
Ans. 1700 men.

33. From 5 different green balls, four different blue balls and three   different red balls, how many combinations of balls can be chosen taking at least   one green and one blue ball?
Ans. 3720.

34. Three pipes, A, B, & C are attached to a tank. A & B can fill it in 20   & 30 minutes respectively while C can empty it in 15 minutes. If A, B & C   are kept open successively for 1 minute each, how soon will the tank be filled?
Ans. 167 minutes.

35. A person walking 5/6 of his usual rate is 40 minutes late. What is his usual time? Ans. 3 hours 20 minutes.