So, the way I learn a new programming skill is I get an idea for a program I need to learn the language (or improve my knowledge of it) to create. Then as I learn the things I need to know, I toy with various ideas and do little experiments just to see what happens or what's possible.

This time I wanted to know if I could get a string name passed, then use it in some function using the eval() function to get its value. For example

var steve="blue";
var blue="danny";
alert(eval(steve));

Now, if it was just alert(steve), the result would be an alert window with the message "blue". But because eval is evaluating the content of "steve" as code... The value of "steve" is "blue" and the value of the variable "blue" is "danny", so alert(eval(steve)) generates an alert window with the message "danny".

But the cool thing is that you can nest evals...

<script type="text/javascript">

var steve="blue";
var blue="danny";

function gotoit(sedley){
alert(eval(eval(sedley)));
}

</script>

<a href="javascript:gotoit('steve');">Run The Dang Script</a>

In this case, the value of sedley is "steve", which evaluates to "blue", which has the value of "danny".

Try it for yourself.

I know, sort of pointless, but it was neat to me and I thought I'd share.

This entry was posted on Tuesday, August 11th, 2009 at 6:45 pm and is filed under Techno Thoughts, Web Programming. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.