Question:
I've been using eval in my code and I recently found out that there can be serious security issues If eval() is used inside Javascript. The most common scenario is where I'm using eval() to compose a variable name and then get the value of that variable like here;
var a = "2" // could be any value work(a); function work(a) { var l1 = "something"; var l2 = "something else"; var l3 = "something different"; alert(eval("l"+a)); // alerts "something else" }; Are there any alternatives to eval() in a situation like this ??
I've tried using window["l"+a] but that will only work if the variables were global and also document.getElementById("l"+a) and that doesn't work either.
Any help greatly appreciated.
Thanks, Norman.
Solution:1
perhaps use an object or an array:
var obj = { '1' : 'something', '2' : 'something else', 'foo' : 'entirely different' }; // access like this: obj[1]; // "something" obj['foo']; // "entirely different" var key = 'foo'; obj[key]; // "entirely different" or, as an array:
var arr = [ "something", "something else", "something different" ]; arr[0] // something arr[1] // something else
Solution:2
use:
window["l"+a] e.g.
var a = "2" // could be any value work(a); function work(a) { l1 = "something"; l2 = "something else"; l3 = "something different"; alert(window["l"+a]); // alerts "something else" }; Alternatively, you could use an array or object notation (preferred as it doesn't pollute global)
var a = "2" // could be any value work(a); function work(a) { var l = ["something", "something else", "something different" ]; alert(l[a]); // alerts "something else" };
Solution:3
use a switch
function match(a) { switch(a) { case 1: alert("something"); break; case 2: alert("something else"); break; case 3: alert("something different"); break; default: alert("No match!"); } } Note:If u also have question or solution just comment us below or mail us on toontricks1994@gmail.com
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