Javascript closures – variable scope question

by

Its because at the time item.help is evaluated, the loop would have completed in its entirety. Instead, you can do this with a closure:

for (var i = 0; i < helpText.length; i++) {
   document.getElementById(helpText[i].id).onfocus = function(item) {
           return function() {showHelp(item.help);};
         }(helpText[i]);
}

JavaScript doesn’t have block scope but it does have function-scope. By creating a closure, we are capturing the reference to helpText[i] permanently.

More Related Contents:

  1. JavaScript closure inside loops – simple practical example
  2. Event handlers inside a Javascript loop – need a closure?
  3. Please explain the use of JavaScript closures in loops [duplicate]
  4. Access outside variable in loop from Javascript closure [duplicate]
  5. Doesn’t JavaScript support closures with local variables? [duplicate]
  6. JavaScript variable binding and loop
  7. How does a function in a loop (which returns another function) work? [duplicate]
  8. Javascript closure not working
  9. Closures in a for loop
  10. passing index from for loop to ajax callback function (JavaScript)
  11. Passing values to onclick [duplicate]
  12. Closure in Javascript [duplicate]
  13. How are local variables referenced in closures? [duplicate]
  14. JavaScript Variable Scope [duplicate]
  15. javascript closure immediate evaluation [duplicate]
  16. I want to print odd numbers using javascript [closed]
  17. Which is the fastest way to loop? [for curiosity]
  18. Looping through array and removing items, without breaking for loop
  19. Assign click handlers in for loop
  20. Javascript efficiency: ‘for’ vs ‘forEach’ [closed]
  21. How should I call 3 functions in order to execute them one after the other?
  22. What’s the best way to break from nested loops in JavaScript?
  23. What’s the best way to loop through a set of elements in JavaScript?
  24. How to use setInterval function within for loop
  25. How To Solve The React Hook Closure Issue?
  26. How to loop through array in jQuery?
  27. Is a closure for dereferencing variables useful?
  28. dynamically call local function in javascript
  29. Javascript: Get access to local variable or variable in closure by its name [duplicate]
  30. Looping through Markers with Google Maps API v3 Problem

Leave a Comment