As tens of thousands of javascript scholar, I encountered the same problem: Uncaught TypeError: Can not read property 'display' of undefined
But my situation is more special, then check online solutions to the same problem, and I find that I do not have a similar, we can not solve my problem.
Yes, I can only debug one, delete deletion change, finally found the answer.
1. I define the style of nodes using a class, with getElementsByClassName to get
var turn = document.getElementsByClassName("turn");2. But the class is a class set of elements is an array, returns all elements of class, then modify the style of the time I still use obj.style, there have been cases not read property
picture.style.display = "none"3. Solution: replace the class with id is the simplest modifications
Html tags into the node id, css, js file the appropriate changes, you can use getElementById to get property
var turn = document.getElementById("turn");summary:
getElementByClassName
This method does not return a specified element but a kind of element, namely the elements class names of all class set for you, so it returns the result should be an array, then you need to change the style from the array to take elements, and then for the element to set attributes, rather than directly set the properties array, so naturally invalid.
Usage (getElement s ByClassName Do not miss the s, behind the use of the specified array elements [0]):
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The following methods are explained;
the getElementById () method returns the element with the specified ID is: [return element]
getElementsByTagName () returns all elements with the specified tag name. [Return a collection of elements that the array]
getElementsByClassName () method
The final conclusion: This Summary section is reproduced, invasion deleted. Original https://www.imooc.com/qadetail/230436
