Only squared working on calculator
<p>This is suppose to be a JavaScript calculator but no calcuation seem to go through except for square which is odd. for example, add, subtract, divide and multiply would not give me an answer even if I insert numbers. I don't know what is wrong with it.</p>

<p>Thanks for your help!</p>

<pre><code>    &lt;/style&gt;

    &lt;script type="text/javascript"&gt;
        &lt;!-- JAVASCRIPT FUNCTIONS GO HERE --&gt;
        var numberOne="", symbol="", numberTwo=""
        function equation (number){
            if(symbol==""){
                numberOne+=number
                document.getElementById('equation').value = numberOne;
            }
            else if(symbol!=""){
                numberTwo+=number
                document.getElementById('equation').value = numberTwo;
            }   
        }
        function getSymbol(operator){
            symbol=operator
            document.getElementById('equation').value = symbol;
        }

        function clear_equation () {
            document.getElementById('equation').value = "";
            numberOne=""
            numberTwo=""
            symbol=""
        }

        function remove () {
            Current = "0";{
            document.Calculator.Display.value = Current;
            }
        }

        function add(num1, num2) {
            output=Number(num1)+Number(num2)
            document.getElementById('equation').value = output;
        }
        function subtract(num1, num2) {
            output=Number(num1)-Number(num2)
            document.getElementById('equation').value = output;
        }
        function multiply(num1, num2) {
            output=Number(num1)*Number(num2)
            document.getElementById('equation').value = output;
        }
        function divide(num1, num2) {
            output=Number(num1)/Number(num2)
            document.getElementById('equation').value = output;
        }
        function sqrt(num1) {
            output=Number(num1)*Number(num1)
            document.getElementById('equation').value = output;
        }
        function sin(num1) {
            output=Math.sin(num1)
            document.getElementById('equation').value = output;
        }
        function solve (add) {
            if(symbol=="+"){
                add(numberOne, numberTwo)
            }
        }
        function solve (subtract) {
            if(symbol=="-"){
                subtract(numberOne, numberTwo)
            }
        }
        function solve (mutiply){
            if(symbol=="*"){
                mutiply(numberOne, numberTwo)
            }
        }
        function solve (divide) {
            if(symbol=="/"){
                divide(numberOne, numberTwo)
            }
        }
        function solve (sqrt) {
            if(symbol=="sqrt"){
                multiply(numberOne, numberOne)
            }
        }

    &lt;/script&gt;
&lt;/head&gt;
&lt;body&gt;
    &lt;div class="container"&gt;
        &lt;table cellspacing="0"&gt;
            &lt;tr&gt;
                &lt;td colspan="5"&gt;&lt;input class="equ" type="input" disabled="disabled" id="equation" value=""/&gt;&lt;/td&gt;
            &lt;/tr&gt;
            &lt;tr&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="sin" onclick="getSymbol (this.value)" /&gt;&lt;/td&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="cos" onclick="getSymbol (this.value)" /&gt;&lt;/td&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="tan" onclick="getSymbol (this.value)" /&gt;&lt;/td&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="sqrt" onclick="getSymbol (this.value)" /&gt;&lt;/td&gt;
            &lt;/tr&gt;
            &lt;tr&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="&amp;larr;" onclick="remove ();"/&gt;&lt;/td&gt;
                &lt;td colspan="2"&gt;&lt;input class="buttons" type="button" value="C" onclick="clear_equation (this.value)" /&gt;&lt;/td&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="/" onclick="getSymbol (this.value)"/&gt;&lt;/td&gt;
            &lt;/tr&gt;
            &lt;tr&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="7" onclick="equation (this.value)"/&gt;&lt;/td&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="8" onclick="equation (this.value)"/&gt;&lt;/td&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="9" onclick="equation (this.value)"/&gt;&lt;/td&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="*" onclick="getSymbol (this.value)"/&gt;&lt;/td&gt;
            &lt;/tr&gt;
            &lt;tr&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="4" onclick="equation (this.value)"/&gt;&lt;/td&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="5" onclick="equation (this.value)"/&gt;&lt;/td&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="6" onclick="equation (this.value)"/&gt;&lt;/td&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="-" onclick="getSymbol (this.value)"/&gt;&lt;/td&gt;
            &lt;/tr&gt;
            &lt;tr&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="1" onclick="equation (this.value)"/&gt;&lt;/td&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="2" onclick="equation (this.value)"/&gt;&lt;/td&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="3" onclick="equation (this.value)"/&gt;&lt;/td&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="+" onclick="getSymbol (this.value)"/&gt;&lt;/td&gt;
            &lt;/tr&gt;
            &lt;tr&gt;
                &lt;td colspan="2"&gt;&lt;input class="buttons" type="button" value="0" onclick="equation (this.value)"/&gt;&lt;/td&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="." onclick="equation (this.value)"/&gt;&lt;/td&gt;
                &lt;td&gt;&lt;input class="buttons" type="button" value="=" onclick="solve ();"/&gt;&lt;/td&gt;
            &lt;/tr&gt;
        &lt;/table&gt;
    &lt;/div&gt;
&lt;/body&gt;
&lt;/html&gt;
</code></pre>
