JavaScript Search Wildcard

Hi,

I’m using the JS below on a SharePoint 2013 On-Prem custom list to add search functionality. It works fine but it has a serious limitation. It will only yield results on a string if the search is an exact match. For example, if I were to search the “Vendor” field below with “Dell” then records with, for example, “Dell Inc.” wouldn’t display so I was wondering how to modify this code so that it would accept wildcards or just automatically search the string if it contains any part of the text being searched for?

Thanks

<script type="text/javascript">

	function Search() {
		var st = document.getElementById("Searchtext").value;
		var cd = document.getElementById("coldropdown").value;
		var url = "";
		
		if(st !="") {
			if(cd == "ID" || cd == "Title" || cd =="Author" || cd == "Vendor") {
				url = "FilterField1=" + cd + "&FilterValue1=" + st;
				window.location.href = "AllItems.aspx?" + url;
			}
			else {
				url = "FilterName=" + cd + "&FilterMultiValue=*" + st + "*";
				window.location.href = "AllItems.aspx?" + url;
			}
		}
		else {
			return false;
		}
	}
	function Clear() {
		window.location.href = "AllItems.aspx";
	}
	</script>
	
	
	Search Field: <select id="coldropdown">
	<option value="ID">ID</option>
	<option value="Title">Title</option>	
	<option value="Author">Created by</option>
	<option value="Vendor">Vendor</option>
	</select>
	Search text: <input id="Searchtext" type="text"/>
	<input id="btnSearch" onclick="return Search();" type="button" value="Search"/>
	<input id="btnSearch" onclick="return Clear();" type="button" value="Clear"/>