techpreparation-homepage

Home  Interview Questions  Certifications  Aptitude Questions  Tutorials  Placement Papers  Search  Resume  Soft Skills  Video  Forum  Blog

Android app on Google Play

Technical Interview Questions
Oracle Interview Questions
J2EE Interview Questions
C++ Interview Questions
XML Interview Questions
EJB Interview Questions
JSP Interview Questions
                              .........More

Programming Source Codes
Java Source Codes
Html Source Codes
CSS Source Codes
C Source Codes
                              .........More

Soft Skills
Communication Skills
Leadership Skills
                              .........More


 

 

  

Javascript Interview Questions and Answers



How to create a popup warning box
alert('Warning: Please enter an integer between 0 and 100.');

How to create a confirmation box?
confirm("Do you really want to launch the missile?"); 

How to create an input box?
prompt("What is your temperature?");

How to setting a cookie with the contents of a textbox ?
Values stored in cookies may not have semicolons, commas, or spaces. You should use the handy "escape()" function to encode the values, and "unescape()" to retrieve them.

//Sets cookie of current value for myTextBox
function TextBoxOnchange() {
var myBox = window.document.getElementById(myTextBox");
document.cookie = "myTextBox="+ escape(myBox.value) + getExpirationString();
}

//return a string like ";expires=Thu, 5 Jan 2006 16:07:52 UTC"
function getExpirationString() {
var exp = new Date();
var threemonths = exp.getTime()+(120*24*60*60*1000);
exp.setTime(threemonths);
return ";expires="+exp.toGMTString();
}

This is called from the event handler in the HTML.

<input name="myTextBox" type="text" id="myTextBox"
onchange="javascript:TextBoxOnchange()" />

How to getting values from cookies to set widgets?
function getCookieData(labelName) {
//from Danny Goodman
var labelLen = labelName.length;
// read cookie property only once for speed
var cookieData = document.cookie;
var cLen = cookieData.length;
var i = 0;
var cEnd;
while (i < cLen) {
var j = i + labelLen;
if (cookieData.substring(i,j) == labelName) {
cEnd = cookieData.indexOf(";",j);
if (cEnd == -1) {
cEnd = cookieData.length;
}
return unescape(cookieData.substring(j+1, cEnd));
}
i++;
}
return "";
}

//init() is called from the body tag onload function.
function init() {
setValueFromCookie("brand");
setValueFromCookie("market");
setValueFromCookie("measure");
}

function setValueFromCookie(widget) {
if( getCookieData(widget) != "") {
document.getElementById(widget).value = getCookieData(widget);
}
}

//if you name your cookies the widget ID, you can use the following helper function
function setCookie(widget) {
document.cookie = widget + "=" +
escape(document.getElementById(widget).value) + getExpirationString();

}

How to change style on an element?
Between CSS and javascript is a weird symmetry. CSS style rules are layed on top of the DOM. The CSS property names like "font-weight" are transliterated into "myElement.style.fontWeight". The class of an element can be swapped out. For example:
document.getElementById("myText").style.color = "green";
document.getElementById("myText").style.fontSize = "20";
-or-
document.getElementById("myText").className = "regular";

Page Numbers :   1       2       3       4       5       6       7        8        9       10        11       12       13

Have a Question ? post your questions here. It will be answered as soon as possible.

Check Java Interview Questions for more Java Interview Questions with answers

Check Structs Interview Questions for more Structs Interview Questions with answers

Check Servlet Interview Questions for more Servlet Interview Questions with answers