In our last article I filled your puny brain with the knowledge of JavaScript operators. In this article we are going to learn about pop-up boxes. That's right, those sometimes annoying, sometimes helpful things that leap out at the user and ask them to do stuff will be covered here.
Javascript Pop-up Boxes - Prompting the Prompt Box (Page 4 of 4 )
Next we are going to create a program to insult people using a Prompt Box. The prompt box asks for a value. If the user inputs one and clicks OK, it will return the value to our program; if they click CANCEL, it will return a null value.
<html>
<head>
<script type="text/javascript">
function disp_prompt()
{
var name=prompt("Enter Your Name for a Prediction","Some Loser")
if (name!=null && name!="")
{
document.write("Hello " + name + "! I predict you will not have a date this weekend!")
}
}
</script>
</head>
<body>
<input type="button" onclick="disp_prompt()" value="Click for a Friendly Greeting" />
</body>
</html>
Again, we have decided to allow the user to push a button to trigger our pop-up. Remember how we were lured into a false sense of security with those Jack in the Boxes? Well this is the digital version. We even give the text box a nice caption so people think everything will be okay: Click for a Friendly Greeting
When the user clicks the button it asks the user to Enter a Name for A Prediction. It displayed a default value of Some Loser (this is where things begin to go downhill for the user muahahah). Whatever they type into the prompt (and then press OK) it will then say:
Hello James! I predict you will not have a date this weekend!
Where James is the value they typed in.
If they clicked the CANCEL button, nothing would have occurred.
If we wanted to do the above without using a button for the user to press (ie; we prompted the user when the page loaded) we could do so this way:
<html>
<head>
<script type="text/javascript">
{
var name=prompt("Enter Your Name for a Prediction","Some Loser")
if (name!=null && name!="")
{
document.write("Hello " + name + "! I predict you will not have a date this weekend!")
}
}
</script>
</head>
<body>
</body>
</html>
The same result without the user having to click the button.
Well, that's it for this episode. Have fun scaring small children with your pop-up boxes; I know I will.
And be sure to come back for the next tutorial, where we discuss Functions.
Till then...
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JavaScript 
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OnReset, OnResize and Other JavaScript Events
