Try & Catch

[Mikeyham]

Why is there a "+" before the equal sign in this try & catch statement?

catch(err)  {  txt="There was an error on this page.\n\n";  txt+="Error description: " + err.description + "\n\n";  txt+="Click OK to continue.\n\n";  alert(txt);  }

~Thanks!

[jeffman]

x = 3; y = 7; x += y; // x returns 10x = "hello"; y = ", world"; x += y; // x returns "hello, world"x += y is shorthand for x = x + ySometimes programmers like to add strings in parts for easier updates and debugging.

[Mikeyham]

I see. I also have another question about the Try & Catch tutorial.

catch(err)  {  txt="There was an error on this page.\n\n";  txt+="Click OK to continue viewing this page,\n";  txt+="or Cancel to return to the home page.\n\n";  if(!confirm(txt))	{	document.location.href="http://www.w3schools.com/";	}

Why is there an "!" before the word "confirm" and, if we are confirming, why is it that when you hit cancel it runs the code?

[Ingolme]

I see. I also have another question about the Try & Catch tutorial.

catch(err)  {  txt="There was an error on this page.\n\n";  txt+="Click OK to continue viewing this page,\n";  txt+="or Cancel to return to the home page.\n\n";  if(!confirm(txt))	{	document.location.href="http://www.w3schools.com/";	}

Why is there an "!" before the word "confirm" and, if we are confirming, why is it that when you hit cancel it runs the code?

Because "!" means "not". It returns the opposite value of the variable that it's negating.If confirm(txt) is true, !confirm(txt) is false.

[Mikeyham]

Because "!" means "not". It returns the opposite value of the variable that it's negating.If confirm(txt) is true, !confirm(txt) is false.

Coolio. That's all. Thanks for the help!