Programming Basics

To learn a computer programming language it is necessary to understand the concepts of sequence, looping, and conditional branching.

Sequence - Doing things in a defined order

Here is a simple script to illustrate sequence. Copy it into the head portion of a simple HTML document, call it "sequence.html" and then open it in a Netscape web browser. To view the completed page, click here.

<SCRIPT language="JavaScript">
document.write("This line of text is the result of the first command in the sequence.<BR>");
document.write("This line of text is the result of the second command in the sequence.<BR>");
document.write("This line of text is the result of the third command in the sequence.<BR>");
</SCRIPT>

Looping - Doing things over and over again

Here is a simple script to illustrate looping. Copy it into the head portion of a simple HTML document, call it "looping.html" and then open it in a Netscape web browser. To view the completed page, click here.

<SCRIPT language="JavaScript">
for (i=10;i>0;i--){
document.write(i + " bottles of beer on the wall.<BR>");
}
</SCRIPT>

Conditional Branching - Doing things only if certain conditions are true.

Here is a simple script to illustrate conditional branching or decision making. Copy it intothe head portion of a simple HTML document, call it "conditionals.html" and then open it in a Netscape web browser. To view the completed page, click here.

<SCRIPT language="JavaScript">

gender = window.prompt("Are you male or female?","");

if (gender == "female"){
document.write("Greetings Madame.<BR>");
}

if (gender == "male"){
document.write("Greetings Sir.<BR>");
}

if (gender != "male" && gender != "female"){
document.write("Please don't confuse me.<BR>");
}

</SCRIPT>