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Eval()


Chocolate570

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Well, i was making a calculator and was having trouble with the + operator because the input was from a text box, making it a string. I went to w3schools, and found the eval function. It worked. :) But i want to know, what happens if you throw letters at it? I tried using it for a thing that stops any letters in the text box at the top of the calculator...but it didn't work. I found out how to do that, but what does it do?Thanks in Advance.Choco

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Think of it as if it didn't have eval around it at all - so if you've got:3 + 6 + youit's going to error, unless you have a variable called you. It's a useful thing for converting text to javascript statements, like:

<script type='text/javascript'>var t = 8var i = eval("3+5+t");alert(i);</script>

If you can understand that.

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What if inside the variable "t" was the letters "abc"? What would it give? An error?

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Yup. Unless you had a variable called abc.

eval() is a function to evaluate a piece of javascript code, like so:
eval("alert('Hello')");

Notice two things:1: The code must be inside quotes ( "" )2: The code inside the quotes cannot end with a semi-colon ( ; ), which means you can only evaluate 1 line of code at a time.I had to use eval() when I made my own game... :):)

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