Skip to main content

Function in Java Script

A function is a process that incorporates a sequence of java script statement to accomplish a task. To integrate a function into document you have to first define it within a SCRIPT, which is contained in the in the head element. Then you have to call function. Calling the function can be accomplished in several ways, including the ability to call a function from within another function. In many instances function is called as the value of an event handler of an HTML element, which is called attribute assignment. The simplest way to call a function is to use it by name as statement. You can use the return statement to return a value with a function. It’s usually a good idea to define functions in the head of document so that functions are loaded first, before any of the HTML elements in the body have loaded. This precludes the generation of many java script runtime errors due to a script in one part of document trying to interact with another script that hasn’t loaded yet. This occurs when the user tries to click a button object before the page fully loads, and button needs that unloaded code before it will work. Since that required code hasn’t loaded yet, you get a runtime error. There are exceptions to HEAD Scripts.

Defining a function with function statement

Defining a function starts by using function keywords, which is followed by the name of function and then a comma-separated list of arguments that are enclosed within parentheses. You can define a function that takes no arguments, but you still have to include the parentheses. Next comes a sequence of Statements that are semicolon separated and enclosed within curly braces {}. The following function setColor() takes no Argument and sets the background color to blue when it is called.

Function setColor()
{
document.bgcolor=”blue”;

Syntax:

Function functionName(argument1, argument 2,………,argument)
{
Statement 1;
Statement 2;
}

Calling a function by attribute assignment

Defining a function is the first step in getting a function to execute its Statements. Next you have to call function within a SCRIIPT or you have to assign it to an event handler of an html element, which is shown in the following example:
To start the process for this scenario you could code previously defined setColor() function so that it was more useful by adding a color Argument to it like this.

Function setColor(color)
{
Document.bgcolor=color;
}

So that when setColor() function is called, background will be changed to color argument that is provided at that time, which can be different each time function is called. For instance, suppose you define three button Objects that each have setColor() function assigned to its respective onClick Event Handler, like this:

<input type=”button” value=”red it” onClick=”setColor(‘red’);”>
<input type=”button” value=”blue it” onClick=”setColor(‘blue’);”>
<input type=”button” value=”green it” onClick=”setColor(‘green’);”>

Then, if the user clicks on the first button, setColor() function uses String ‘red’ as the color argument to change the background color to red. If the user clicks on the second Button, the onClick Event Handler uses the same setColor() function but has a different String value to provide as the color argument so that the background color gets changed to blue. The same is true for the button with ‘green’ as the color argument.

Comments

Popular posts from this blog

difference between structure and union in C Language

In c language article we will see the difference between union and structure. Both are the user define datatype in c language. See the table which is mentioned below: ASP.NET Video Tutorial Series Structure Union1.The keywordstruct is used to define a structure 1. The keyword union is used to define a union. 2. When a variable is associated with a structure, the compiler allocates the memory for each member. The size of structure is greater than or equal to the sum ofsizes of its members. The smaller members may end with unused slack bytes. 2. When a variable is associated with a union, thecompiler allocates thememory by considering the size of the largest memory. So, size of union is equal to the size of largest member. 3. Each member within a structure is assigned unique storage area of location. 3. Memory allocated is shared by individual members of union. 4. The address of each member will be in ascending order This indicates that memory for each member will start at different offset v…

Difference between Linear search and Binary Search in c language

SQL Video Channel : Download all SQL Video



Binary Search Linear Search Works only on sorted items. such as  1,2,3,4,5,6  etc
Works on sorted as well as unsorted items. 12,4,5,3,2,1 etc Very efficient if the items are sorted Very efficient if the items are less and present in the beginning of the list. such as Suppose your list items are : 12,3,4,5,1 and you want to search 12 number then you get beginning in the list. Works well with arrays and not on linked lists. Works with arrays and linked lists.
Number of comparisons are less More number of comparisons are required if the items are present in the later part of the array or its elements are more.

Memory representation of Linked List Data Structures in C Language

Memory representation of Linked List

             In memory the linked list is stored in scattered cells (locations).The memory for each node is allocated dynamically means as and when required. So the Linked List can increase as per the user wish and the size is not fixed, it can vary.

               Suppose first node of linked list is allocated with an address 1008. Its graphical representation looks like the figure shown below:


      Suppose next node is allocated at an address 506, so the list becomes,



  Suppose next node is allocated with an address with an address 10,s the list become,


The other way to represent the linked list is as shown below:




 In the above representation the data stored in the linked list is “INDIA”, the information part of each node contains one character. The external pointer root points to first node’s address 1005. The link part of the node containing information I contains 1007, the address of next node. The last node …