JavaScript: Basics plus - build on your JavaScript knowledge
This page introduces the basics of JavaScript code constructs with examples.
JavaScript code snippets listed by task and organised in a tutorial style each building on the previous example. New topics are introduced when required.
1 |
Use of character data (CDATA) section: a refinement on the comment notation for hiding script and used for shielding JavaScript code that contains special characters such as <, >, & and " from the browser without the need to use character or numeric entity reference values. CDATA sections: a requirement for XML and therefore XHTML. Problems with most browsers and current compromise solution.
Note: placing your functions in an external .js function library file will remove the need to include the CDATA section, see JavaScript: Basics code snippet 3. |
2. |
Performing a Boolean condition test: true or false. Simple test on (2<3) and (2>3). Use of the 'valueOf()' method to return the true or false value. |
3. |
Selection: based on a true or false condition. Building an 'if else' conditional with 'NOT' operator '!'. Use of equality operator '=='. Function calling another function. |
4. |
Building an 'if else' conditional with 'OR' comparison operator '||'. Acting on user input from 'window.prompt()'. |
4a. |
Shortcut notation 'if else' conditional. Introducing the shortcut notation for the 'if else' conditional. Sometimes known as a ternary operator with the syntax '?:', a conditional expression equivalent to an 'if then else' and incorporated in a ternary statement: condition ? if true : if false |
5. |
Building a nested 'if else' conditional. Acting on user input from 'window.prompt()'. |
6. |
Building a multiple 'if' conditional with 'AND' comparison operator '&&'. Acting on user input from 'window.prompt()'. Same output as snippet 5 above but layout of code clearer. |
7. |
Repetition: building a simple 'while loop'. Incorporating XHTML elements into output. Example: '<br />'. |
8. |
Repetition: building a simple 'for loop'. Ideal if the loop body is to be repeated a known number of times. |
9. |
Use of 'switch' statement structure with 'case' and 'break'. Including a default 'case' if none of the statements match. |
10. |
Build on the above and learn about the JavaScript Array object. View code examples on JavaScript: Arrays page. |
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