diff --git a/index.html b/index.html
index 9a9dc1a..df4f33b 100644
--- a/index.html
+++ b/index.html
@@ -3,7 +3,6 @@
     
 
 <head>
-    <script async src="trigocal.js"></script>
     <meta charset="utf-8">
     <meta name="viewport" content="width=device-width, initial-scale=1">
     <link rel="icon" href="assets/trigo.png" type="image/icon">
@@ -202,7 +201,7 @@ <h2>Trigonometric functions</h2>
         <hr width=90% color="#E5C480">
         <a href="mailto:abhijeetkr.sci@gmail.com"><img src="assets/feedback.png" height="65" width="200"></a>
 
-        <script src="trigocal.js"></script>
+        <script src="trigocal.js" defer></script>
         <script>
             function calcright() {
                 var i1 = document.getElementById("degtype1").selectedIndex;
diff --git a/trigocal.js b/trigocal.js
index bf62fc0..f44b688 100644
--- a/trigocal.js
+++ b/trigocal.js
@@ -1,73 +1,37 @@
 function setfocus() {
-    document.calcform.x.focus();
+    document.getElementById("x").focus();
 }
 
 function calc() {
-    x = document.calcform.x.value;
-    y = calcfunc(x);
-    y = roundresult(y);
-    document.calcform.y.value = y
-}
+    let x = parseFloat(document.getElementById("x").value);
 
-function calc_a() {
-    x = document.calcform2.x.value;
-    y = calcfunc_a(x);
-    y = roundresult(y);
-    document.calcform2.y.value = y
-}
+    if (isNaN(x)) {
+        document.getElementById("y").value = "Invalid input";
+        return;
+    }
 
-function calc3() {
-    x1 = document.calcform.x.value;
-    x2 = document.calcform.x2.value;
-    y = calcfunc(x1, x2);
-    y = roundresult(y);
-    document.calcform.y.value = y;
-}
+    let func = document.getElementById("func").value;
+    let y;
 
-function calc4() {
-    a = document.calcform.x.value;
-    b = document.calcform.x2.value;
-    c = document.calcform.x3.value;
-    d = b * b - 4 * a * c;
-    document.calcform.y0.value = roundresult(d);
-    if (d >= 0) {
-        document.calcform.y1.value = roundresult((-b + Math.sqrt(d)) / (2 * a));
-        document.calcform.y2.value = roundresult((-b - Math.sqrt(d)) / (2 * a));
-    } else {
-        re = roundresult(-b / (2 * a));
-        im = roundresult(Math.sqrt(-d) / (2 * a));
-        document.calcform.y1.value = re + ' + i' + im;
-        document.calcform.y2.value = re + ' - i' + im;
-    }
-    b = -b;
-    document.calcform.y3.value = '(' + b.toString() + ' \xb1 \u221A(' + d.toString() + ')) / (2\xd7' + a.toString() + ')';
-}
+    if (func === "sin") y = Math.sin(x);
+    else if (func === "cos") y = Math.cos(x);
+    else if (func === "tan") y = Math.tan(x);
+    else if (func === "csc") y = 1 / Math.sin(x);
+    else if (func === "sec") y = 1 / Math.cos(x);
+    else if (func === "cot") y = 1 / Math.tan(x);
 
-function calc5() {
-    x = document.calcform.x.value;
-    y = calcfunc(x);
     y = roundresult(y);
-    if (x > 0) y = '\u00B1' + y;
-    document.calcform.y.value = y
+    document.getElementById("y").value = y;
 }
 
-function calc6() {
-    x1 = document.calcform.x.value;
-    x2 = document.calcform.x2.value;
-    val = x2;
-    if (x2 < 0) val = -val;
-    y = calcfunc(x1, val);
+function calc_a() {
+    let x = parseFloat(document.getElementById("x").value);
+    let y = calcfunc_a(x);
     y = roundresult(y);
-    if (x2 > 0 && (x1 / 2) == Math.round(x1 / 2)) y = '\u00B1' + y;
-    if (x2 < 0) {
-        if ((x1 / 2) == Math.round(x1 / 2))
-            y = 'NaN';
-        else
-            y = -y;
-    }
-    document.calcform.y.value = y;
+    document.getElementById("y").value = y;
 }
 
+
 function str2num(s) {
     s = s.toString().trim().replace(/(\d)(\s+)(?=\d)/gm, "$1+").replace(/[^-()\d/*+.]/g, '');
     if (s == '') return 0;
@@ -75,7 +39,7 @@ function str2num(s) {
 }
 
 function roundresult(x) {
-    y = parseFloat(x);
+    let y = parseFloat(x);
     y = roundnum(y, 10);
     return y;
 }
@@ -87,7 +51,7 @@ function roundnum(x, p) {
     var y = String(m);
     i = y.indexOf('e');
     if (i == -1) i = y.length;
-    j = y.indexOf('.');
+    let j = y.indexOf('.');
     if (i > j && j != -1) {
         while (i > 0) {
             if (y.charAt(--i) == '0')
@@ -107,7 +71,7 @@ function roundnum2(x, p) {
     var m = n.toFixed(p);
     var y = String(m);
     i = y.length;
-    j = y.indexOf('.');
+    let j = y.indexOf('.');
     if (i > j && j != -1) {
         while (i > 0) {
             if (y.charAt(--i) == '0')
