6. Program to change color of the text box if empty string submitted.

<script>
function funup(val)
{
if(val.length>0) document.getElementById('t1').style.borderColor="silver";
}
function fun1()
{
txt=document.getElementById('t1').value if(txt.length == 0) document.getElementById('t1').style.borderColor = "red"
}
</script>

<input type="text" id="t1" onkeyup="funup(this.value)">
<input type="button" value="Submit" onclick="fun1()">

7. Write a JavaScript program to display the current day and time in the following format.

<script>
var today = new Date();
var day = today.getDay();
var daylist=["Sunday"
,"Monday","Tuesday"
,"Wednesday","Thursday","Friday",
"Saturday"];

console.log("Today is : " + daylist[day] + ".");

var hour = today.getHours();
var minute = today.getMinutes();
var second = today.getSeconds();
var prepand = (hour >= 12)? " PM ":" AM ";
hour = (hour >= 12)? hour - 12: hour;

if (hour===0 && prepand===' PM ')
{
if (minute===0 && second===0)
{
hour=12;
prepand=' Noon';
}
else
{
hour=12;
prepand=' PM';
}
}
if (hour===0 && prepand===' AM ')
{
if (minute===0 && second===0)
{
hour=12;
prepand=' Midnight';
}
else
{
hour=12;
prepand=' AM';
}
}

console.log("Current Time : "+hour + prepand + " : " + minute + " : " + second);

</script>

8. Write a JavaScript program to get the current date.

<script>

var today = new Date();
var dd = today.getDate();

var mm = today.getMonth()+1;
var yyyy = today.getFullYear();

if(dd<10)
{
dd='0'+dd;
}

if(mm<10)
{
mm='0'+mm;
}

today = mm+'-'+dd+'-'+yyyy;
console.log(today);

today = mm+'/'+dd+'/'+yyyy;
console.log(today);

today = dd+'-'+mm+'-'+yyyy;
console.log(today);

today = dd+'/'+mm+'/'+yyyy;
console.log(today);

</script>

9. Write a JavaScript function to find the area of a triangle where lengths of the three of its sides are 5, 6, 7.

<script>

var side1 = 5;
var side2 = 6;
var side3 = 7;

var s = (side1 + side2 + side3)/2;
var area = Math.sqrt(s*((s-side1)*(s-side2)*(s-side3)));
console.log(area);

</script>

10. Write a JavaScript program to determine whether a given year is a leap year in the Gregorian calendar.

<script>

year = window.prompt("Input a Year : ");
x = (year % 100 === 0) ? (year % 400 === 0) : (year % 4 === 0);
console.log(x);

</script>

11. Write a JavaScript program to find which 1st January is being a Sunday between 2014 and 2050.

<script>
console.log('--------------------');

for (var year = 2014; year <= 2050; year++)
{

var d = new Date(year, 0, 1);
if ( d.getDay() === 0 )
console.log("1st January is being a Sunday "+year);
}

console.log('--------------------');
</script>

12. Write a JavaScript program to calculate number of days left until next Christmas.

<script>
today=new Date();
var cmas=new Date(today.getFullYear(), 11, 25);

if (today.getMonth()==11 && today.getDate()>25)
{
cmas.setFullYear(cmas.getFullYear()+1);
}

var one_day=1000*60*60*24;

console.log(Math.ceil((cmas.getTime()-today.getTime())/(one_day))+
" days left until Christmas!");
</script>

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13. Write a JavaScript program to convert temperatures to and from celsius, fahrenheit.


function cToF(celsius)
{
var cTemp = celsius;
var cToFahr = cTemp * 9 / 5 + 32;
var message = cTemp+'\xB0C is ' + cToFahr + ' \xB0F.';
console.log(message);
}

function fToC(fahrenheit)
{
var fTemp = fahrenheit;
var fToCel = (fTemp - 32) * 5 / 9;
var message = fTemp+'\xB0F is ' + fToCel + '\xB0C.';
console.log(message);
}
cToF(60);
fToC(45);

14. Write a JavaScript program to check if two numbers are in range 40..60 or in the range 70..100 inclusive.

function numbers_ranges(x, y) {
if ((x >= 40 && x <= 60 && y >= 40 && y <= 60)
||
(x >= 70 && x <= 100 && y >= 70 && y <= 100))
{
return true;
}
else
{
return false;
}
}

console.log(numbers_ranges(44, 56));
console.log(numbers_ranges(70, 95));
console.log(numbers_ranges(50, 89));

15. Write a JavaScript program to check if the last digit of the three given positive integers is same.  

function last_digit(x, y, z)
{
if ((x > 0) && y > 0 && z > 0)
{
return (x % 10 == y % 10 && y % 10 == z % 10 && x % 10 == z % 10);
}
else
return false;
}

console.log(last_digit(20, 30, 400));
console.log(last_digit(-20, 30, 400));
console.log(last_digit(20, -30, 400));
console.log(last_digit(20, 30, -400));

16. Write a JavaScript program to create a new string with first 3 characters are in lower case from a given string. If the string length is less than 3 convert all the characters in upper case.

function upper_lower(str) {
if (str.length < 3) {
return str.toUpperCase();
}
front_part = (str.substring(0, 3)).toLowerCase();
back_part = str.substring(3, str.length);
return front_part + back_part;
}
console.log(upper_lower("Python"));
console.log(upper_lower("Py"));
console.log(upper_lower("JAVAScript"));

17. Write a JavaScript program to compute the absolute difference between a specified number and 19. Returns triple their absolute difference if the specified number is greater than 19.

function diff_num(n) {
if (n <= 19) {
return (19 - n);
}
else
{
return (n - 19) * 3;
}
}

console.log(diff_num(12));
console.log(diff_num(19));
console.log(diff_num(22));

18. Write a JavaScript program to check two given numbers and return true if one of the number is 50 or if their sum is 50.

function test50(x, y)
{
return ((x == 50 || y == 50) || (x + y == 50));
}
console.log(test50(50, 50))
console.log(test50(20, 50))
console.log(test50(20, 20))
console.log(test50(20, 30))

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19. Write a JavaScript program to check a given integer is within 20 of 100 or 400

function testhundred(x) {
return ((Math.abs(100 - x) <= 20) ||
(Math.abs(400 - x) <= 20));
}

console.log(testhundred(10));
console.log(testhundred(90));
console.log(testhundred(99));
console.log(testhundred(199));
console.log(testhundred(200));

20. Write a JavaScript program to check from two given integers, if one is positive and one is negative.

function positive_negative(x, y)
{
if ((x < 0 && y > 0) || x > 0 && y < 0)
{
return true;
}
else
{
return false;
}
}
console.log(positive_negative(2, 2));
console.log(positive_negative(-2, 2));
console.log(positive_negative(2, -2));
console.log(positive_negative(-2, -2));

21. Write a JavaScript program to create a new string adding "Py" in front of a given string. If the given string begins with "Py" then return the original string.

function string_check(str1) {
if (str1 === null || str1 === undefined || str1.substring(0, 2) === 'Py')
{
return str1;
}
return "Py"+str1;
}

console.log(string_check("Python"));
console.log(string_check("thon"));

22. Write a JavaScript program to remove a character at the specified position of a given string and return the new string.

function remove_character(str, char_pos)
{
part1 = str.substring(0, char_pos);
part2 = str.substring(char_pos + 1, str.length);
return (part1 + part2);
}

console.log(remove_character("Python",0));
console.log(remove_character("Python",3));
console.log(remove_character("Python",5));

23. Write a JavaScript program to create a new string from a given string changing the position of first and last characters. The string length must be greater than or equal to 1.

function first_last(str1)
{
if (str1.length <= 1)
{
return str1;
}
mid_char = str1.substring(1, str1.length - 1);
return (str1.charAt(str1.length - 1)) + mid_char + str1.charAt(0);
}
console.log(first_last('a'));
console.log(first_last('ab'));
console.log(first_last('abc'));