_basicCustomElementTest = function _basicCustomElementTest(tagName) {
		return tagName.indexOf('-') > 0;
	}
_basicCustomElementCheck
checks if at least one dash is included in tagName, and it's not the first char
for more sophisticated checking see https://github.com/sindresorhus/validate-element-name
@param {string} tagName name of the tag of the node to sanitize