javascript forEach - 在所有按钮上添加 addEventListener
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javascript forEach - add addEventListener on all buttons
提问by David Madhatter
I'm not so skilled with javascript so I'm looking for a little help. I'm using a script found on Codrops (3D Grid Effect - http://tympanus.net/Development/3DGridEffect/).
我对 javascript 不是很熟练，所以我正在寻找一些帮助。我正在使用在 Codrops 上找到的脚本（3D 网格效果 - http://tympanus.net/Development/3DGridEffect/）。
All is working fine as expected but I'm trying to "modify" it for my needs.
一切正常，但我正在尝试根据我的需要“修改”它。
Basically, I want to trigger the "effect" NOT clicking on the whole container but on a button placed inside it.
基本上，我想触发“效果”，而不是点击整个容器，而是点击放置在其中的按钮。
The structure I'm using is:
我使用的结构是：
<section class="grid3d vertical" id="grid3d">
<div class="grid-wrap">
<div class="grid">
<div class="box"><div class="btn-click-me">Click to Show</div></div>
<div class="box"><div class="btn-click-me">Click to Show</div></div>
<div class="box"><div class="btn-click-me">Click to Show</div></div>
</div>
</div>
<div class="content">
<div>
<div class="dummy-img"></div>
<p class="dummy-text">Some text</p>
<p class="dummy-text">Some more text</p>
</div>
<div>
<!-- ... -->
</div>
<!-- ... -->
<span class="loading"></span>
<span class="icon close-content"></span>
</div>
</section>
<script>
new grid3D( document.getElementById( 'grid3d' ) );
</script>
And the script (js) is
而脚本（js）是
/**
* grid3d.js v1.0.0
* http://www.codrops.com
*
* Licensed under the MIT license.
* http://www.opensource.org/licenses/mit-license.php
*
* Copyright 2014, Codrops
* http://www.codrops.com
*/
;( function( window ) {
'use strict';
function grid3D( el, options ) {
this.el = el;
this.options = extend( {}, this.options );
extend( this.options, options );
this._init();
}
// any options you might want to configure
grid3D.prototype.options = {};
grid3D.prototype._init = function() {
// grid wrapper
this.gridWrap = this.el.querySelector( 'div.grid-wrap' );
// grid element
this.grid = this.gridWrap.querySelector( 'div.grid' );
// main grid items
this.gridItems = [].slice.call( this.grid.children );
// default sizes for grid items
this.itemSize = { width : this.gridItems[0].offsetWidth, height : this.gridItems[0].offsetHeight };
// content
this.contentEl = this.el.querySelector( 'div.content' );
// content items
this.contentItems = [].slice.call( this.contentEl.children );
// close content cross
this.close = this.contentEl.querySelector( 'span.close-content' );
// loading indicator
this.loader = this.contentEl.querySelector( 'span.loading' );
// support: support for pointer events, transitions and 3d transforms
this.support = support.pointerevents && support.csstransitions && support.csstransforms3d;
// init events
this._initEvents();
};
grid3D.prototype._initEvents = function() {
var self = this;
// open the content element when clicking on the main grid items
this.gridItems.forEach( function( item, idx ) {
item.addEventListener( 'click', function() {
self._showContent( idx );
} );
} );
// close the content element
this.close.addEventListener( 'click', function() {
self._hideContent();
} );
if( this.support ) {
// window resize
window.addEventListener( 'resize', function() { self._resizeHandler(); } );
// trick to prevent scrolling when animation is running (opening only)
// this prevents that the back of the placeholder does not stay positioned in a wrong way
window.addEventListener( 'scroll', function() {
if ( self.isAnimating ) {
window.scrollTo( self.scrollPosition ? self.scrollPosition.x : 0, self.scrollPosition ? self.scrollPosition.y : 0 );
}
else {
self.scrollPosition = { x : window.pageXOffset || docElem.scrollLeft, y : window.pageYOffset || docElem.scrollTop };
// change the grid perspective origin as we scroll the page
self._scrollHandler();
}
});
}
};
// creates placeholder and animates it to fullscreen
// in the end of the animation the content is shown
// a loading indicator will appear for 1 second to simulate a loading period
grid3D.prototype._showContent = function( pos ) {
if( this.isAnimating ) {
return false;
}
this.isAnimating = true;
var self = this,
loadContent = function() {
// simulating loading...
setTimeout( function() {
// hide loader
classie.removeClass( self.loader, 'show' );
// in the end of the transition set class "show" to respective content item
classie.addClass( self.contentItems[ pos ], 'show' );
}, 1000 );
// show content area
classie.addClass( self.contentEl, 'show' );
// show loader
classie.addClass( self.loader, 'show' );
classie.addClass( document.body, 'noscroll' );
self.isAnimating = false;
};
// if no support just load the content (simple fallback - no animation at all)
if( !this.support ) {
loadContent();
return false;
}
var currentItem = this.gridItems[ pos ],
itemContent = currentItem.innerHTML;
// create the placeholder
this.placeholder = this._createPlaceholder(itemContent );
// set the top and left of the placeholder to the top and left of the clicked grid item (relative to the grid)
this.placeholder.style.left = currentItem.offsetLeft + 'px';
this.placeholder.style.top = currentItem.offsetTop + 'px';
// append placeholder to the grid
this.grid.appendChild( this.placeholder );
// and animate it
var animFn = function() {
// give class "active" to current grid item (hides it)
classie.addClass( currentItem, 'active' );
// add class "view-full" to the grid-wrap
classie.addClass( self.gridWrap, 'view-full' );
// set width/height/left/top of placeholder
self._resizePlaceholder();
var onEndTransitionFn = function( ev ) {
if( ev.propertyName.indexOf( 'transform' ) === -1 ) return false;
this.removeEventListener( transEndEventName, onEndTransitionFn );
loadContent();
};
self.placeholder.addEventListener( transEndEventName, onEndTransitionFn );
};
setTimeout( animFn, 25 );
};
grid3D.prototype._hideContent = function() {
var self = this,
contentItem = this.el.querySelector( 'div.content > .show' ),
currentItem = this.gridItems[ this.contentItems.indexOf( contentItem ) ];
classie.removeClass( contentItem, 'show' );
classie.removeClass( this.contentEl, 'show' );
// without the timeout there seems to be some problem in firefox
setTimeout( function() { classie.removeClass( document.body, 'noscroll' ); }, 25 );
// that's it for no support..
if( !this.support ) return false;
classie.removeClass( this.gridWrap, 'view-full' );
// reset placeholder style values
this.placeholder.style.left = currentItem.offsetLeft + 'px';
this.placeholder.style.top = currentItem.offsetTop + 'px';
this.placeholder.style.width = this.itemSize.width + 'px';
this.placeholder.style.height = this.itemSize.height + 'px';
var onEndPlaceholderTransFn = function( ev ) {
this.removeEventListener( transEndEventName, onEndPlaceholderTransFn );
// remove placeholder from grid
self.placeholder.parentNode.removeChild( self.placeholder );
// show grid item again
classie.removeClass( currentItem, 'active' );
};
this.placeholder.addEventListener( transEndEventName, onEndPlaceholderTransFn );
}
// function to create the placeholder
/*
<div class="placeholder">
<div class="front">[content]</div>
<div class="back"></div>
</div>
*/
grid3D.prototype._createPlaceholder = function( content ) {
var front = document.createElement( 'div' );
front.className = 'front';
front.innerHTML = content;
var back = document.createElement( 'div' );
back.className = 'back';
back.innerHTML = ' ';
var placeholder = document.createElement( 'div' );
placeholder.className = 'placeholder';
placeholder.appendChild( front );
placeholder.appendChild( back );
return placeholder;
};
grid3D.prototype._scrollHandler = function() {
var self = this;
if( !this.didScroll ) {
this.didScroll = true;
setTimeout( function() { self._scrollPage(); }, 60 );
}
};
// changes the grid perspective origin as we scroll the page
grid3D.prototype._scrollPage = function() {
var perspY = scrollY() + getViewportH() / 2;
this.gridWrap.style.WebkitPerspectiveOrigin = '50% ' + perspY + 'px';
this.gridWrap.style.MozPerspectiveOrigin = '50% ' + perspY + 'px';
this.gridWrap.style.perspectiveOrigin = '50% ' + perspY + 'px';
this.didScroll = false;
};
grid3D.prototype._resizeHandler = function() {
var self = this;
function delayed() {
self._resizePlaceholder();
self._scrollPage();
self._resizeTimeout = null;
}
if ( this._resizeTimeout ) {
clearTimeout( this._resizeTimeout );
}
this._resizeTimeout = setTimeout( delayed, 50 );
}
grid3D.prototype._resizePlaceholder = function() {
// need to recalculate all these values as the size of the window changes
this.itemSize = { width : this.gridItems[0].offsetWidth, height : this.gridItems[0].offsetHeight };
if( this.placeholder ) {
// set the placeholders top to "0 - grid offsetTop" and left to "0 - grid offsetLeft"
this.placeholder.style.left = Number( -1 * ( this.grid.offsetLeft - scrollX() ) ) + 'px';
this.placeholder.style.top = Number( -1 * ( this.grid.offsetTop - scrollY() ) ) + 'px';
// set the placeholders width to windows width and height to windows height
this.placeholder.style.width = getViewportW() + 'px';
this.placeholder.style.height = getViewportH() + 'px';
}
}
// add to global namespace
window.grid3D = grid3D;
})( window );
Now, I'm aware that the "crucial" portion of the code where I have to look is:
现在，我知道我必须查看的代码的“关键”部分是：
// open the content element when clicking on the main grid items this.gridItems.forEach( function(item, idx ) { item.addEventListener( 'click', function() { item._showContent( idx ); } ); } );
// 点击主网格项时打开内容元素 this.gridItems.forEach( function(item, idx ) { item.addEventListener( 'click', function() { item._showContent( idx ); } ); } ) ;
So, my question again: how to trigger the event when the div (button) class "click-me" is clicked on every "boxes"?
所以，我再次提出问题：如何在每个“框”上单击 div（按钮）类“click-me”时触发事件？
Thanks to all in advance (i'm struggling with it for hours...)
提前感谢所有人（我已经挣扎了几个小时......）
回答by Rob Schmuecker
Have a look at the example here,
看看这里的例子，
I have added some intialisation to get your particular classes
我添加了一些初始化来获取您的特定课程
// get grid buttons and then make an iterable array out of them
this.gridButtons = this.el.querySelectorAll('button.btn-click-me');
this.gridButtonItems = [].slice.call(this.gridButtons);
and changed the function which iterates and adds a listener.
并更改了迭代和添加侦听器的函数。
// open the content element when clicking on the buttonsItems
this.gridButtonItems.forEach(function (item, idx) {
item.addEventListener('click', function () {
self._showContent(idx);
});
});
回答by Fernando Porazzi
If you want to call a callback function when the user clicks on a button:
如果要在用户单击按钮时调用回调函数：
var buttons = document.querySelectorAll('.btn-click-me');
for (var i = 0; i < buttons.length; i++) {
var self = buttons[i];
self.addEventListener('click', function (event) {
// prevent browser's default action
event.preventDefault();
// call your awesome function here
MyAwesomeFunction(this); // 'this' refers to the current button on for loop
}, false);
}
回答by Alvaro Pinot
with the structure given
与给定的结构
<div class="grid-wrap">
<div class="grid">
<div class="box"><div class="btn-click-me">Click to Show</div></div>
<div class="box"><div class="btn-click-me">Click to Show</div></div>
<div class="box"><div class="btn-click-me">Click to Show</div></div>
</div>
</div>
you just have to change the line you've said to:
你只需要改变你所说的行：
item.children[0].addEventListener( 'click', function() {
as the btn-click-me would be the first child of each item.
因为 btn-click-me 将是每个项目的第一个子项。
If you would like a more generic solution you could use:
如果您想要更通用的解决方案，可以使用：
item.getElementsByClassName('btn-click-me')[0].addEventListener( 'click', function() {
where bnt-click-mewould be the class of the button that you would want to bind the click event. Notice that [0]so you can select the very first item of the array, as getElementsByClassNamewill return one, even if there's only one element.
其中bnt-click-me将是您想要绑定点击事件的按钮的类。请注意，[0]因此您可以选择数组的第一个项目getElementsByClassName，即使只有一个元素，也会返回一个。
But if you say you're just starting with javascript y really recommend you using jQuery, it's selectors are much easier than vanilla javascript.
但是，如果您说您刚开始使用 javascript ，那么您真的建议您使用jQuery，它的选择器比vanilla javascript容易得多。
