JS Calculator Updated For Cross Browser Support!!

<center>
<title>Calculator</title>
<h4>Input:</h4>
<input value="0"; id="Input" name="Input"</input>
<br>
<h4>Keypad:</h4>
<input type="button"; value=" 1 "; onclick="javascript:
var IntHolder;
var IntHolder0;
IntHolder=(1);
Input.value=(IntHolder);
"></input>
<input type="button"; value=" 2 "; onclick="javascript:
var IntHolder;
var IntHolder0;
IntHolder=(2);
Input.value=(IntHolder);
"></input>
<input type="button"; value=" 3 "; onclick="javascript:
var IntHolder;
var IntHolder0;
IntHolder=(3);
Input.value=(IntHolder);
"></input>
<br>
<input type="button"; value=" 4 "; onClick="javascript:
var IntHolder
var IntHolder0
IntHolder=(4);
Input.value=(IntHolder);
"></input>
<input type="button"; value=" 5 "; onClick="javascript:
var IntHolder
var IntHolder0
IntHolder=(5);
Input.value=(IntHolder);
"></input>
<input type="button"; value=" 6 "; onClick="javascript:
var IntHolder
var IntHolder0
IntHolder=(6);
Input.value=(IntHolder);
"></input>
<br>
<input type="button"; value=" 7 "; onClick="javascript:
var IntHolder
var IntHolder0
IntHolder=(7);
Input.value=(IntHolder);
"></input>
<input type="button"; value=" 8 "; onClick="javascript:
var IntHolder
var IntHolder0
IntHolder=(8);
Input.value=(IntHolder);
"></input>
<input type="button"; value=" 9 "; onClick="javascript:
var IntHolder
var IntHolder0
IntHolder=(9);
Input.value=(IntHolder);
"></input>
<br>
<input type="button"; value="      0      "; onClick="javascript:
var IntHolder
var IntHolder0
IntHolder=(0);
Input.value=(IntHolder);
"></input>
<h4>Input:</h4>
<input value="0"; id="Input1" name="Input1"</input>
<h4>Keypad:</h4>
<input type="button"; value=" 1 "; onClick="javascript:
var IntHolder
var IntHolder0
IntHolder=(1);
Input1.value=(IntHolder);
"></input>
<input type="button"; value=" 2 "; onClick="javascript:
var IntHolder
var IntHolder0
IntHolder=(2);
Input1.value=(IntHolder);
"></input>
<input type="button"; value=" 3 "; onClick="javascript:
var IntHolder
var IntHolder0
IntHolder=(3);
Input1.value=(IntHolder);
"></input>
<br>
<input type="button"; value=" 4 "; onClick="javascript:
var IntHolder
var IntHolder0
IntHolder=(4);
Input1.value=(IntHolder);
"></input>
<input type="button"; value=" 5 "; onClick="javascript:
var IntHolder
var IntHolder0
IntHolder=(5);
Input1.value=(IntHolder);
"></input>
<input type="button"; value=" 6 "; onClick="javascript:
var IntHolder
var IntHolder0
IntHolder=(6);
Input1.value=(IntHolder);
"></input>
<br>
<input type="button"; value=" 7 "; onClick="javascript:
var IntHolder
var IntHolder0
IntHolder=(7);
Input1.value=(IntHolder);
"></input>
<input type="button"; value=" 8 "; onClick="javascript:
var IntHolder
var IntHolder0
IntHolder=(8);
Input1.value=(IntHolder);
"></input>
<input type="button"; value=" 9 "; onClick="javascript:
var IntHolder
var IntHolder0
IntHolder=(9);
Input1.value=(IntHolder);
"></input>
<br>
<input type="button"; value="      0      " onclick="javascript:
var IntHolder
var IntHolder0
IntHolder=(0);
Input1.value=(IntHolder);
"></input>

<h4>Operators:</h4>
<input type="button"; value=" + "; onClick="javascript:
var IntHolder
IntHolder=Number(Input.value) + Number(Input1.value)
Output.value=(IntHolder);
"></input>
<input type="button"; value=" - "; onClick="javascript:
var IntHolder
IntHolder=Input.value - Input1.value
Output.value=(IntHolder);
"></input>
<input type="button"; value=" X "; onClick="javascript:
var IntHolder
IntHolder=Input.value * Input1.value
Output.value=(IntHolder);
"></input>
<input type="button"; value=" / "; onClick="javascript:
var IntHolder
IntHolder=Input.value / Input1.value
Output.value=(IntHolder);
"></input>
<br>
<br>
<h4>Result:</h4>
<input value=""; id="Output" name="Output"</input>
</center>