Programming Errors and Screen Objects

Syntax errors are caused by illegal operations, for example, division by zero, or accessing a non-existent area of memory.

Screen objects are used to retrieve information about the client's screen, including properties like screen height, width, color depth, etc.

The unshift() method adds one or more elements to the beginning of an array and returns the new length of the array.

<p>escape() encodes a string for transferring over a network, while unescape() decodes the encoded string back to its original form.</p> Signup and view all the answers

<p>Namespacing helps in organizing functions and variables under a unique name, promoting modularity and code reuse.</p> Signup and view all the answers

<p>To hide JavaScript code from older browsers, wrap the code in '' just before the closing tag.</p> Signup and view all the answers

<p>Generic objects can be created as: var I = new object();</p> Signup and view all the answers

<p>To return a string description of a variable type</p> Signup and view all the answers

<p>Exceptions can be handled using try...catch...finally blocks.</p> Signup and view all the answers

<p>The 'document.write' method is used to print text on the screen.</p> Signup and view all the answers

<p>The 'blur' function is used to remove focus from a specified object.</p> Signup and view all the answers

<p>To add elements to the end of an array</p> Signup and view all the answers

<p>The 'Navigator.appVersion' is used to find the operating system in the client machine.</p> Signup and view all the answers

<p>The three types of errors in JavaScript are: load time errors, run-time errors, and logical errors.</p> Signup and view all the answers

<p>The status of a CheckBox can be checked using 'document.getElementById('checkbox1').checked'.</p> Signup and view all the answers

<p>Closures in JavaScript are locally declared variables associated with a function, which remain in memory even after the function has returned.</p> Signup and view all the answers

<p>JavaScript is a client-side as well as server side scripting language that can be inserted into HTML pages and is understood by web browsers. It is also an Object based Programming language.</p> Signup and view all the answers

<p>Java is a complete programming language. In contrast, JavaScript is a coded program that can be introduced to HTML pages. While Java is object-oriented, like C++ or C, JavaScript is a client-side scripting language.</p> Signup and view all the answers

<p>Number, String, Boolean, Function, Object, Undefined.</p> Signup and view all the answers

<p>isNaN function returns true if the argument is not a number; otherwise, it returns false.</p> Signup and view all the answers

<p>JavaScript is faster as it is a client-side language that does not rely on the web server to execute.</p> Signup and view all the answers

<p>Negative Infinity is a number in JavaScript that can be derived by dividing a negative number by zero.</p> Signup and view all the answers

<p>Yes, breaking within a string statement can be done using a backslash at the end of the first line.</p> Signup and view all the answers

<p>Netscape is the software company that developed JavaScript.</p> Signup and view all the answers

<p>Undeclared variables do not exist in a program and are not declared. Undefined variables are declared but not given a value.</p> Signup and view all the answers

<p>function addNode() { var newP = document.createElement(&quot;p&quot;); var textNode = document.createTextNode(&quot;This is a new text node&quot;); newP.appendChild(textNode); document.getElementById(&quot;firstP&quot;).appendChild(newP); }</p> Signup and view all the answers

<p>Global variables are available throughout the code and have no scope. They are declared using the var keyword.</p> Signup and view all the answers

<p>A prompt box is a dialog box that allows users to input text or numbers.</p> Signup and view all the answers

<p>The 'this' keyword refers to the object from which it was called.</p> Signup and view all the answers

<p>Timers are used to execute code at a set time or interval. setTimeout is used to run a function after a delay, setInterval repeats a function, and clearInterval stops the timer. Drawbacks include events queuing up in a single thread.</p> Signup and view all the answers

<p>// is used for single line comments in JavaScript.</p> Signup and view all the answers

<p>ViewState is specific to a page in a session, while SessionState is specific to user data accessible across all pages of a web application.</p> Signup and view all the answers

<p>=== is the strict equality operator in JavaScript that returns true only if the operands have the same value without type conversion.</p> Signup and view all the answers

<p>To submit a form using JavaScript, use document.form.submit();</p> Signup and view all the answers

<p>Yes, JavaScript supports automatic type conversion which is commonly used by developers.</p> Signup and view all the answers

<p>The style or class of an element can be changed using JavaScript by modifying properties like fontSize or className.</p> Signup and view all the answers

<p>There are two ways to read and write files in JavaScript: Using JavaScript extensions or using a web page and Active X objects.</p> Signup and view all the answers

<p>The looping structures in JavaScript include for, while, and do-while loops.</p> Signup and view all the answers

<p>Variable typing in JavaScript refers to the ability to assign different data types to a variable.</p> Signup and view all the answers

<p>To convert the string of any base to an integer in JavaScript, use the parseInt() function with the base specified.</p> Signup and view all the answers

<p>'==' checks only for value equality, while '===' checks for both value and type equality.</p> Signup and view all the answers

<p>The result would be 57 because the integers 3 and 2 will be added numerically, while the string '7' will be concatenated.</p> Signup and view all the answers

<p>To detect the operating system on the client machine, use the navigator.platform property.</p> Signup and view all the answers

<p>NULL in JavaScript represents the absence of a value or object, indicating no valid data type.</p> Signup and view all the answers

<p>The delete operator is used to delete a property along with its value in JavaScript objects.</p> Signup and view all the answers

<p>Undefined value in JavaScript signifies a variable that doesn't exist, is unassigned, or a property that doesn't exist.</p> Signup and view all the answers

<p>The types of pop up boxes available in JavaScript are Alert, Confirm, and Prompt.</p> Signup and view all the answers

<p>Void(0) is used to call a function without refreshing the page by passing zero as a parameter.</p> Signup and view all the answers

<p>To force a page to load another page in JavaScript, appropriate script injections or navigation methods need to be used.</p> Signup and view all the answers

<p>All variables in JavaScript are object data types.</p> Signup and view all the answers

<p>An alert box displays only an OK button, while a confirmation box displays both OK and Cancel buttons.</p> Signup and view all the answers

<p>Escape characters, denoted by a backslash, are used to work with special characters by indicating how they should be displayed.</p> Signup and view all the answers

<p>Cookies in JavaScript are small text files stored in a computer to save specific information, like user details or preferences, for future visits.</p> Signup and view all the answers

<p>The pop() method removes the last element from an array in JavaScript and returns that element.</p> Signup and view all the answers

<p>No, JavaScript does not have concept-level scope. Variables declared inside a function have scope only within that function.</p> Signup and view all the answers

<p>The disadvantages of using innerHTML in JavaScript include content replacement everywhere, limited append functionality, and performance issues with re-parsing entire content.</p> Signup and view all the answers

<p>The break statement exits the current loop, while the continue statement skips the current iteration and moves to the next statement of the loop.</p> Signup and view all the answers

<p>The two basic groups of data types in JavaScript are Primitive types (number, boolean) and Reference types (like strings and dates).</p> Signup and view all the answers