JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://ajax.cdnjs.com/ajax/libs/underscore.js/1.1.4/underscore-min.js"></script>
<script src="http://ajax.cdnjs.com/ajax/libs/backbone.js/0.3.3/backbone-min.js"></script>
<div id="search_container">a</div>
<script type="text/template" id="search_template">
    <label>Search</label>
    <input type='number' id="search_input" />
</script>

JavaScript

SearchView = Backbone.View.extend({
        initialize: function(){
            this.render();
        },
        render: function(){
            var template = _.template( $("#search_template").html(), {} );
            this.el.html( template );
        },
        events: {
            //"beforeinput #search_input":"typeOfField"
        },
       typeOfField:function(event){
            //finding Ascii value of the press key
           var keyAsciiValue=event.keyCode||event.which;
           alert(keyAsciiValue);
           //declaring dummy variable for passing result
           var result=false;
           if ((keyAsciiValue>=48&&keyAsciiValue<=57)||(keyAsciiValue===46)||(keyAsciiValue===45)){
                //text-field allows any numbers like 23.8,30...
                result=true;
               //alert("number"+keyAsciiValue);
            }else{
                result=false;
                //alert("character"+keyAsciiValue);
            };
            return result;
	    }
    });
    
    var search_view = new SearchView({ el: $("#search_container") });