MDN wants to learn about developers like you: https://qsurvey.mozilla.com/s3/MDN-dev-survey

This translation is incomplete. Please help translate this article from English.

הודעה

TypeError: "x" is not a function

סוג השגיאה

TypeError.

מה השתבש?

It attempted to call a value like a function, but the value is not actually a function. Some code expects you to provide a function, but that didn't happen.

Maybe there is a typo in the function name? Maybe the object you are calling the method on does not have this function? For example, JavaScript objects have no map function, but JavaScript Array object do.

There are many built-in functions in need of a (callback) function. You will have to provide a function in order to have these methods working properly:

דוגמאות

טעות בשם הפונקציה

במקרה כזה, שקורה לעתים קרובות, יש טעות בשם המתודה:

var x = document.getElementByID("foo");
// TypeError: document.getElementByID is not a function

השם הנכון של הפונקציה הוא getElementById:

var x = document.getElementById("foo");

הפונקציה קראה לפריט הלא נכון

For certain methods, you have to provide a (callback) function and it will work on specific objects only. In this example, Array.prototype.map() is used, which will work with Array objects only.

var obj = { a: 13, b: 37, c: 42 };

obj.map(function(num) {
  return num * 2;
});

// TypeError: obj.map is not a function

ניתן להשתמש במערך במקום:

var numbers = [1, 4, 9];

numbers.map(function(num) { 
  return num * 2; 
}); 

// Array [ 2, 8, 18 ]

מידע נוסף

Document Tags and Contributors

 Contributors to this page: YaronSh
 Last updated by: YaronSh,