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copied!<p>Move <code>changeValue()</code> to be in the same scope as <code>i</code>:</p> <pre><code>function myFunction(){ var i; for(i=0;i<3;i++){ alert(i); changeValue(); alert(i); } function changeValue() { i = 99; } } </code></pre> <p>Or, put <code>i</code> in the same scope as <code>changeValue()</code>:</p> <pre><code>var i; function changeValue() { i = 99; } function myFunction(){ // var i; // don't define i here for(i=0;i<3;i++){ alert(i); changeValue(); alert(i); } } </code></pre> <p>Alternatively, you can tell <code>changeValue()</code> what the value of <code>i</code> is, then have it return the new value:</p> <pre><code>function changeValue(i) { return i + 1; } </code></pre> <p>Then:</p> <pre><code>i = changeValue(i); </code></pre> <p><strong>Edit:</strong> To illustrate scope:</p> <pre><code>var a = 0; // global scope - accessible everywhere via a // unless overridden by a locally scoped a // always accessible via window.a function doSomething () { var a = 1; // local scope - you can still access window.a var b = 2; // local scope - accessible to child scopes, but not global scope function innerFunction () { var a = 3; // you no longer have access to the parent function's a variable // you can still access window.a var c = 4; // only accessible here (since no child scopes exist) alert(window.a); // 0 alert(a); // 3 alert(b); // 2 alert(c); // 4 } innerFunction(); alert(window.a); // 0 alert(a); // 1 alert(b); // 2 alert(c); // undefined - unavailable in this scope } doSomething(); alert(window.a); // 0 alert(a); // 0 alert(b); // undefined - unavailable in this scope alert(c); // undefined - unavailable in this scope </code></pre>

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