JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" id="txt1" value="13/06/2013" />

<br />

<select id="ddlHourTime">
    <option>06</option>
    <option>08</option>
    <option>09</option>
    <option>10</option>
    <option>11</option>
    <option>12</option>
    <option>13</option>
    <option>14</option>
    <option>15</option>
    <option>16</option>
    <option>17</option>
    <option>18</option>
    <option>19</option>
</select>

<br />

<select id="ddlMinuteTime">
    <option>00</option>
    <option>15</option>
    <option>30</option>
    <option>45</option>
</select>

<br /><br />

<input type="button" id="btn1" value="test" />

JavaScript

function funLoad(str1,str3,str4)
{
    
    var dym1 = str1.split("/");

    var d=new Date();
    var dym2 = d.getMonth() + 1 + "-" + d.getDate() + "-" + d.getFullYear() + " " + d.getHours() + ":" + d.getMinutes() + ":00";
    //var dym2 = "6 10 2013 09:00:00";
    
    var start = Date.parse(dym1[1] + "-" + dym1[0] + "-" + dym1[2] + " " + str3 + ":" + str4 + ":00"); 
    var end = Date.parse(dym2);
    
    return (start-end) / (1000*60*60);

}

$("#btn1").click(function(event){
    alert(funLoad($("#txt1").val(),$("#ddlHourTime").val(),$("#ddlMinuteTime").val()));
});