English in text detection JS

file.js

function changeEngFont(selector) {
$(selector).contents().each(function () {
	if (this.nodeType === 3) {

	} else {
		let value = this.innerHTML;
		let isEnglish = value.search(/[^a-zA-Z]+/);
		if(isEnglish === -1 || isEnglish === 3) {
			$(this).css("font-family", "Baskerville, serif");
		}
	}
});
}

changeEngFont(".content-box"); // shop pane
changeEngFont("#shop_single .text"); // shop single
changeEngFont(".slider-title"); // home slider

home.html

<div class="slider-title">
  <p class="caption"><?php echo $slide->title; ?></p>
</div>