Uncaught typeerror: cannot read property 'queryselector' of null

Question

1.00/5 (1 vote)

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There is an error in js file,line 3 that say:

What I have tried:

(function() {
	var triggerBttn = document.getElementById( 'trigger-overlay' ),
		overlay = document.querySelector( 'div.overlay' ),
		closeBttn = overlay.querySelector( 'button.overlay-close' );
		transEndEventNames = {
			'WebkitTransition': 'webkitTransitionEnd',
			'MozTransition': 'transitionend',
			'OTransition': 'oTransitionEnd',
			'msTransition': 'MSTransitionEnd',
			'transition': 'transitionend'
		},
		transEndEventName = transEndEventNames[ Modernizr.prefixed( 'transition' ) ],
		support = { transitions : Modernizr.csstransitions };
		s = Snap( overlay.querySelector( 'svg' ) ), 
		path = s.select( 'path' ),
		pathConfig = {
			from : path.attr( 'd' ),
			to : overlay.getAttribute( 'data-path-to' )
		};

	function toggleOverlay() {
		if( classie.has( overlay, 'open' ) ) {
			classie.remove( overlay, 'open' );
			classie.add( overlay, 'close' );
			
			var onEndTransitionFn = function( ev ) {
				classie.remove( overlay, 'close' );
			};
			
			path.animate( { 'path' : pathConfig.from }, 400, mina.linear, onEndTransitionFn );
		}
		else if( !classie.has( overlay, 'close' ) ) {
			classie.add( overlay, 'open' );
			path.animate( { 'path' : pathConfig.to }, 400, mina.linear );
		}
	}

	triggerBttn.addEventListener( 'click', toggleOverlay );
	closeBttn.addEventListener( 'click', toggleOverlay );
})();

Posted 10-Oct-17 23:24pm

Member 13341049

Updated 11-Oct-17 0:09am

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Karthik_Mahalingam · Answer 1 · 2017-10-11T00:09:00

Solution 1

Make sure the DOM contains the div element with the class overlay

Quote:
Uncaught typeerror: cannot read property 'queryselector' of null

You will get this error, when you try to access the members of an object which is null, Validate for null values before accessing the members

overlay = document.querySelector('div.overlay'),
          if(overlay != null){  // validate for null value
              closeBttn = overlay.querySelector('button.overlay-close');

Posted 11-Oct-17 0:09am

Karthik_Mahalingam

Comments

Fuad Manaye 8-Oct-21 3:56am

Uncaught TypeError: Cannot read properties of null (reading 'querySelector' how to fix this statement when am coding this line of code
const wrapper = document.querySelector(".wrapper"),
searchInput = wrapper.querySelector("input"),

Karthik_Mahalingam 8-Oct-21 4:34am


const wrapper = document.querySelector(".wrapper"),
if(wrapper!= null) {
searchInput = wrapper.querySelector("input")
}