how to rectify java script runtime error

Hi,

Most internet users have encountered the annoying JavaScript error at some stage. This happens when a script in a web page contains an error or fails to execute correctly. Exactly what happens depends on the browser and type of error, but in most cases some sort of error notification will be displayed.

In Internet Explorer's default setting, a small warning icon appears in the status bar.
Double-click this icon to display a window with the complete error message. You can see the complete error message .

You can choose to have this error window appear automatically whenever an error occurs. This could be annoying for general surfing, but it is very useful when writing your own JavaScript. This is because the error message always lets you know when something is wrong with your code, and even better, it usually tells you exactly where in the HTML document the problem lies

If you are visiting a website which shows an error, you obviously can't fix it but if you're feeling generous you might like to contact the webmaster and let them know. You can still view the page (disabling automatic error messages will make it easier), but whatever the script was supposed to do won't work. This may or may not effect on the functionality of the page.

Fixing JavaScript Errors

There are two types of JavaScript error:
* Syntax Error: Occurs when there is a mistake in the way the code is written; for example, a typo or missing character.
* Runtime error: Occurs when the script is unable to complete its instructions; for example, if a specified object cannot be found.


Example

Syntax Error

The function below contains an error and will result in the error message as pictured. In this case the message tells you that a closing parenthesis is missing.

function showText()
{
alert('something!';
}

Runtime Error

The function below is constructed correctly and will run with no problems as long as the variable something can be found (remember that a text string without quotes is assumed to be a variable). If this variable is not defined an error will occur.

function showText2() {
alert(something);
}
Syntax error messages appear as soon as the page loads, even if the error is inside a function. Runtime error messages appear when the affected code runs, so if an error is inside a function the message will appear when that function is executed.

Thx
Krthika