How to create a calculator in blogger

How to create a calculator in blogger

Table of Contents

In this post we learn about how to create a calculator in blogger website with the help of javascript, css and html.

CSS CODE

.calculator
{
        width:300px;
        height:300px;
        background-color:#eeeeee;
        border:2px solid #CCCCCC;
        margin:auto;
        padding-left:5px;
        padding-bottom:5px;
}
.calculator td
{
        height:16.66%;
}
.calc_td_result
{
        text-align:center;
}
.calc_result
{
        width:90%;
        text-align:right;
}
.calc_td_calculs
{
        text-align:center;
}
.calc_calculs
{
        width:90%;
        text-align:left;
}
.calc_td_btn
{
        width:25%;
        height:100%;
}
.calc_btn
{
        width:90%;
        height:90%;
        font-size:20px;
}

JavaScript Code

calc_array = new Array();
var calcul=0;
var pas_ch=0;
function $id(id)
{
        return document.getElementById(id);
}
function f_calc(id,n)
{
        if(n=='ce')
        {
                init_calc(id);
        }
        else if(n=='=')
        {
                if(calc_array[id][0]!='=' && calc_array[id][1]!=1)
                {
                        eval('calcul='+calc_array[id][2]+calc_array[id][0]+calc_array[id][3]+';');
                        calc_array[id][0] = '=';
                        $id(id+'_result').value=calcul;
                        calc_array[id][2]=calcul;
                        calc_array[id][3]=0;
                }
        }
        else if(n=='+-')
        {
                $id(id+'_result').value=$id(id+'_result').value*(-1);
                if(calc_array[id][0]=='=')
                {
                        calc_array[id][2] = $id(id+'_result').value;
                        calc_array[id][3] = 0;
                }
                else
                {
                        calc_array[id][3] = $id(id+'_result').value;
                }
                pas_ch = 1;
        }
        else if(n=='nbs')
        {
                if($id(id+'_result').value<10 && $id(id+'_result').value>-10)
                {
                        $id(id+'_result').value=0;
                }
                else
                {
                        $id(id+'_result').value=$id(id+'_result').value.slice(0,$id(id+'_result').value.length-1);
                }
                if(calc_array[id][0]=='=')
                {
                        calc_array[id][2] = $id(id+'_result').value;
                        calc_array[id][3] = 0;
                }
                else
                {
                        calc_array[id][3] = $id(id+'_result').value;
                }
        }
        else
        {
                        if(calc_array[id][0]!='=' && calc_array[id][1]!=1)
                        {
                                eval('calcul='+calc_array[id][2]+calc_array[id][0]+calc_array[id][3]+';');
                                $id(id+'_result').value=calcul;
                                calc_array[id][2]=calcul;
                                calc_array[id][3]=0;
                        }
                        calc_array[id][0] = n;
        }
        if(pas_ch==0)
        {
                calc_array[id][1] = 1;
        }
        else
        {
                pas_ch=0;
        }
        document.getElementById(id+'_result').focus();
        return true;
}
function add_calc(id,n)
{
        if(calc_array[id][1]==1)
        {
                $id(id+'_result').value=n;
        }
        else
        {
                $id(id+'_result').value+=n;
        }
        if(calc_array[id][0]=='=')
        {
                calc_array[id][2] = $id(id+'_result').value;
                calc_array[id][3] = 0;
        }
        else
        {
                calc_array[id][3] = $id(id+'_result').value;
        }
        calc_array[id][1] = 0;
        document.getElementById(id+'_result').focus();
        return true;
}
function init_calc(id)
{
        $id(id+'_result').value=0;
        calc_array[id] = new Array('=',1,'0','0',0);
        document.getElementById(id+'_result').focus();
        return true;
}
function key_detect_calc(id,evt)
{
        if((evt.keyCode>95) && (evt.keyCode<106))
        {
                var nbr = evt.keyCode-96;
                add_calc(id,nbr);
        }
        else if((evt.keyCode>47) && (evt.keyCode<58))
        {
                var nbr = evt.keyCode-48;
                add_calc(id,nbr);
        }
        else if(evt.keyCode==107)
        {
                f_calc(id,'+');
        }
        else if(evt.keyCode==109)
        {
                f_calc(id,'-');
        }
        else if(evt.keyCode==106)
        {
                f_calc(id,'*');
        }
        else if(evt.keyCode==111)
        {
                f_calc(id,'');
        }
        else if(evt.keyCode==110)
        {
                add_calc(id,'.');
        }
        else if(evt.keyCode==190)
        {
                add_calc(id,'.');
        }
        else if(evt.keyCode==188)
        {
                add_calc(id,'.');
        }
        else if(evt.keyCode==13)
        {
                f_calc(id,'=');
        }
        else if(evt.keyCode==46)
        {
                f_calc(id,'ce');
        }
        else if(evt.keyCode==8)
        {
                f_calc(id,'nbs');
        }
        else if(evt.keyCode==27)
        {
                f_calc(id,'ce');
        }
        return true;
}

HTML Code

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <title>Javascript Calculator</title>
    </head>
    <body>
        <table class="calculator" id="calc">
            <tr>
                <td colspan="4" class="calc_td_result">
                    <input type="text" readonly="readonly" name="calc_result" id="calc_result" class="calc_result" onkeydown="javascript:key_detect_calc('calc',event);" />
                </td>
            </tr>
            <tr>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="CE" onclick="javascript:f_calc('calc','ce');" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="←" onclick="javascript:f_calc('calc','nbs');" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="%" onclick="javascript:f_calc('calc','%');" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="+" onclick="javascript:f_calc('calc','+');" />
                </td>
            </tr>
            <tr>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="7" onclick="javascript:add_calc('calc',7);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="8" onclick="javascript:add_calc('calc',8);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="9" onclick="javascript:add_calc('calc',9);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="-" onclick="javascript:f_calc('calc','-');" />
                </td>
            </tr>
                        <tr>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="4" onclick="javascript:add_calc('calc',4);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="5" onclick="javascript:add_calc('calc',5);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="6" onclick="javascript:add_calc('calc',6);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="x" onclick="javascript:f_calc('calc','*');" />
                </td>
            </tr>
            <tr>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="1" onclick="javascript:add_calc('calc',1);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="2" onclick="javascript:add_calc('calc',2);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="3" onclick="javascript:add_calc('calc',3);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="÷" onclick="javascript:f_calc('calc','');" />
                </td>
            </tr>
            <tr>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="0" onclick="javascript:add_calc('calc',0);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="±" onclick="javascript:f_calc('calc','+-');" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="," onclick="javascript:add_calc('calc','.');" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="=" onclick="javascript:f_calc('calc','=');" />
                </td>
            </tr>
        </table>
        <script type="text/javascript">
                document.getElementById('calc').onload=init_calc('calc');
        </script>
    </body>
</html>

Final Code

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <title>TechWorld4U Calculator</title>
		<style>
		.calculator
{
        width:300px;
        height:300px;
        background-color:#eeeeee;
        border:2px solid #CCCCCC;
        margin:auto;
        padding-left:5px;
        padding-bottom:5px;
}
.calculator td
{
        height:16.66%;
}
.calc_td_result
{
        text-align:center;
}
.calc_result
{
        width:90%;
        text-align:right;
}
.calc_td_calculs
{
        text-align:center;
}
.calc_calculs
{
        width:90%;
        text-align:left;
}
.calc_td_btn
{
        width:25%;
        height:100%;
}
.calc_btn
{
        width:90%;
        height:90%;
        font-size:20px;
}
		</style>
		<script type="text/javascript">
		calc_array = new Array();
var calcul=0;
var pas_ch=0;
function $id(id)
{
        return document.getElementById(id);
}
function f_calc(id,n)
{
        if(n=='ce')
        {
                init_calc(id);
        }
        else if(n=='=')
        {
                if(calc_array[id][0]!='=' && calc_array[id][1]!=1)
                {
                        eval('calcul='+calc_array[id][2]+calc_array[id][0]+calc_array[id][3]+';');
                        calc_array[id][0] = '=';
                        $id(id+'_result').value=calcul;
                        calc_array[id][2]=calcul;
                        calc_array[id][3]=0;
                }
        }
        else if(n=='+-')
        {
                $id(id+'_result').value=$id(id+'_result').value*(-1);
                if(calc_array[id][0]=='=')
                {
                        calc_array[id][2] = $id(id+'_result').value;
                        calc_array[id][3] = 0;
                }
                else
                {
                        calc_array[id][3] = $id(id+'_result').value;
                }
                pas_ch = 1;
        }
        else if(n=='nbs')
        {
                if($id(id+'_result').value<10 && $id(id+'_result').value>-10)
                {
                        $id(id+'_result').value=0;
                }
                else
                {
                        $id(id+'_result').value=$id(id+'_result').value.slice(0,$id(id+'_result').value.length-1);
                }
                if(calc_array[id][0]=='=')
                {
                        calc_array[id][2] = $id(id+'_result').value;
                        calc_array[id][3] = 0;
                }
                else
                {
                        calc_array[id][3] = $id(id+'_result').value;
                }
        }
        else
        {
                        if(calc_array[id][0]!='=' && calc_array[id][1]!=1)
                        {
                                eval('calcul='+calc_array[id][2]+calc_array[id][0]+calc_array[id][3]+';');
                                $id(id+'_result').value=calcul;
                                calc_array[id][2]=calcul;
                                calc_array[id][3]=0;
                        }
                        calc_array[id][0] = n;
        }
        if(pas_ch==0)
        {
                calc_array[id][1] = 1;
        }
        else
        {
                pas_ch=0;
        }
        document.getElementById(id+'_result').focus();
        return true;
}
function add_calc(id,n)
{
        if(calc_array[id][1]==1)
        {
                $id(id+'_result').value=n;
        }
        else
        {
                $id(id+'_result').value+=n;
        }
        if(calc_array[id][0]=='=')
        {
                calc_array[id][2] = $id(id+'_result').value;
                calc_array[id][3] = 0;
        }
        else
        {
                calc_array[id][3] = $id(id+'_result').value;
        }
        calc_array[id][1] = 0;
        document.getElementById(id+'_result').focus();
        return true;
}
function init_calc(id)
{
        $id(id+'_result').value=0;
        calc_array[id] = new Array('=',1,'0','0',0);
        document.getElementById(id+'_result').focus();
        return true;
}
function key_detect_calc(id,evt)
{
        if((evt.keyCode>95) && (evt.keyCode<106))
        {
                var nbr = evt.keyCode-96;
                add_calc(id,nbr);
        }
        else if((evt.keyCode>47) && (evt.keyCode<58))
        {
                var nbr = evt.keyCode-48;
                add_calc(id,nbr);
        }
        else if(evt.keyCode==107)
        {
                f_calc(id,'+');
        }
        else if(evt.keyCode==109)
        {
                f_calc(id,'-');
        }
        else if(evt.keyCode==106)
        {
                f_calc(id,'*');
        }
        else if(evt.keyCode==111)
        {
                f_calc(id,'');
        }
        else if(evt.keyCode==110)
        {
                add_calc(id,'.');
        }
        else if(evt.keyCode==190)
        {
                add_calc(id,'.');
        }
        else if(evt.keyCode==188)
        {
                add_calc(id,'.');
        }
        else if(evt.keyCode==13)
        {
                f_calc(id,'=');
        }
        else if(evt.keyCode==46)
        {
                f_calc(id,'ce');
        }
        else if(evt.keyCode==8)
        {
                f_calc(id,'nbs');
        }
        else if(evt.keyCode==27)
        {
                f_calc(id,'ce');
        }
        return true;
}
		</script>
    </head>
    <body>
        <table class="calculator" id="calc">
            <tr>
                <td colspan="4" class="calc_td_result">
                    <input type="text" readonly="readonly" name="calc_result" id="calc_result" class="calc_result" onkeydown="javascript:key_detect_calc('calc',event);" />
                </td>
            </tr>
            <tr>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="CE" onclick="javascript:f_calc('calc','ce');" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="←" onclick="javascript:f_calc('calc','nbs');" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="%" onclick="javascript:f_calc('calc','%');" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="+" onclick="javascript:f_calc('calc','+');" />
                </td>
            </tr>
            <tr>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="7" onclick="javascript:add_calc('calc',7);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="8" onclick="javascript:add_calc('calc',8);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="9" onclick="javascript:add_calc('calc',9);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="-" onclick="javascript:f_calc('calc','-');" />
                </td>
            </tr>
                        <tr>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="4" onclick="javascript:add_calc('calc',4);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="5" onclick="javascript:add_calc('calc',5);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="6" onclick="javascript:add_calc('calc',6);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="x" onclick="javascript:f_calc('calc','*');" />
                </td>
            </tr>
            <tr>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="1" onclick="javascript:add_calc('calc',1);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="2" onclick="javascript:add_calc('calc',2);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="3" onclick="javascript:add_calc('calc',3);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="÷" onclick="javascript:f_calc('calc','');" />
                </td>
            </tr>
            <tr>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="0" onclick="javascript:add_calc('calc',0);" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="±" onclick="javascript:f_calc('calc','+-');" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="," onclick="javascript:add_calc('calc','.');" />
                </td>
                <td class="calc_td_btn">
                        <input type="button" class="calc_btn" value="=" onclick="javascript:f_calc('calc','=');" />
                </td>
            </tr>
        </table>
        <script type="text/javascript">
                document.getElementById('calc').onload=init_calc('calc');
        </script>
    </body>
</html>

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