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<title>JavaScript strict mode</title>
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<pre> <!-- Use pre element for work document.writeln() method -->
<script type="text/javascript">
function myFun(){
"use strict";
var var1 = 15; // works
document.writeln(var1);
// Remove below comments and run it again it will throw syntax error
// var2 = 20; // throw the syntax error
}
// Outside of strict mode scope
var3 = 10; // works
document.writeln(var3);
myFun();
</script>
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