Javascript Dynamic Variable (Random number added)

问题

How do I create a dynamic variable in Javascript?

For example, I have:

var myAwesomeText = "Hello World!"

But now I want the varible MyAesomeText to have a random number attached to it every time the page is refreshed. So it would instead look like something like this:

var myAwesomeText12345 = "Hello World!"

And most importantly, how do I call that that new random variable back once the random number has been assigned to it? (i.e: alert(???);)

I've tried something like this, but I'm going wrong with this somewhere.

var myRnd = Math.floor(Math.random()*100000);
var myVar = "MyAwesomeText" + myRnd;
str = myVar + ' = ' + '"Hello World!"';
eval(str);

alert(str);

回答1:

You can access the variable via the window object:

var myRnd = Math.floor(Math.random()*100000);
var myVar = "MyAwesomeText" + myRnd;
window[myVar]  = "Hello World!";

alert(window[myVar]);

Don't use eval for this: it is slower and completely unnecessary for this problem. Also it can have unexpected side-effects if your MyAwesomeText has characters in it that have special meaning in JavaScript code, such as brackets, semi-colon, colon, comma, braces, ... etc.

Note that the notation object['prop'] gives the same result as object.prop. Since global variables are created in the window object, you can access any variable via the window.myvariable notation.

Combining these two facts, you can access global variables that have a dynamic name with window[dynamicVariableName].

回答2:

eval is the way to go

var num = 10;
var string = "var a"+num +"= 'hi'"
string
// "var a10= 'hi'"
eval(string)
a10
// 'hi'

回答3:

You miss one eval on the alert

var myRnd = Math.floor(Math.random()*100000);
var myVar = "MyAwesomeText" + myRnd;
str = myVar + ' = ' + '"Hello World!"';
eval(str);

alert(eval(myVar));

来源：https://stackoverflow.com/questions/37309448/javascript-dynamic-variable-random-number-added

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javascript

variables

random

dynamic