用JavaScript计算小时数

Question

I need to calculate in javascript the hours between jam_keluar and jam_masuk so that lama_parkir will be like:

lama_parkir = jam_keluar - jam_masuk // 4 hours

 function hitunglamaparkir(){ var k = document.getElementById('jam_keluar').value; var m = document.getElementById('jam_masuk').value; var tentukan = (k - m); document.forms.formID.lama_parkir.value = tentukan; } 

 <form id="formID" name="form2" method="post" action="proses.php"> <tr> <td id="noborder">Jam Masuk</td> <td id="noborder">:</td> <td id="noborder"><input name="jam_masuk" type="text" id="jam_masuk" size="5" maxlength="15" value="10:30:00"/> </td> </tr> <tr> <td id="noborder">Jam Keluar</td> <td id="noborder">:</td> <td id="noborder"><input name="jam_keluar" type="text" id="jam_keluar" size="5" onkeyup="hitunglamaparkir(this.value,getElementById('jam_keluar').value);" value="14:30:00"/></td> </tr> <tr> <td id="noborder">Lama Parkir</td> <td id="noborder">:</td> <td id="noborder"><input name="lama_parkir" type="text" id="lama_parkir" size="5" maxlength="15" readonly="readonly"/></td> </form> 

Answer 1

This snippet determines the difference between jam_keluar and jam_keluar as such:

jam_keluar - jam_masuk = lama_parkir .

So we can determine this:

1. Your function is working properly
2. There is no need to call subtotal
3. There is no need for lama_parkir to be editable (make it readonly )

 function hitunglamaparkir(){ var k = document.getElementById('jam_keluar').value; var m = document.getElementById('jam_masuk').value; var tentukan = (k - m); document.forms.formID.lama_parkir.value = tentukan; } 

 <form id="formID" name="form2" method="post" action="proses.php"> <tr> <td id="noborder">Jam Masuk</td> <td id="noborder">:</td> <td id="noborder"><input name="jam_masuk" type="text" id="jam_masuk" size="5" maxlength="15" /> </td> </tr> <tr> <td id="noborder">Jam Keluar</td> <td id="noborder">:</td> <td id="noborder"><input name="jam_keluar" type="text" id="jam_keluar" size="5" onkeyup="hitunglamaparkir(this.value,getElementById('jam_keluar').value);"/></td> </tr> <tr> <td id="noborder">Lama Parkir</td> <td id="noborder">:</td> <td id="noborder"><input name="lama_parkir" type="text" id="lama_parkir" size="5" maxlength="15" readonly="readonly"/></td> </form>