diff --git a/public/main.js b/public/main.js
index a5f54e5..d136d6d 100644
--- a/public/main.js
+++ b/public/main.js
@@ -294,10 +294,12 @@ function enter_matrix() {
 
 	try {
 		entries = JSON.parse(atob(matrix))
-		assert(Array.isArray(entries))
-		assert(entries.length == 2 * dim * dim)
+		if (!Array.isArray(entries)) { throw new Error("Bad object") }
+		if (entries.length != 2 * dim * dim) { throw new Error("Bad length") }
 		for (let i = 0; i < 2 * dim * dim; i++) {
-			assert(!isNaN(entries[i]) && -3 < entries[i] && entries[i] < 3)
+			if (isNaN(entries[i]) || -3 > entries[i] || entries[i] > 3) {
+				throw new Error("Bad entries")
+			}
 		}
 
 		matrix_entries = entries
@@ -358,10 +360,10 @@ function input_update(e) {
 	const i = row * dim * 2 + col * 2;
 	try {
 		let [real, imag] = input.value.split('+');
-		real = Number(real);
-		imag = Number(imag.replace(/i$/, ''));
-		assert(!isNaN(real) && -3 < real && real < 3);
-		assert(!isNaN(imag) && -3 < imag && imag < 3);
+		real = Number(real)
+		imag = Number(imag.replace(/i$/, ''))
+		if (isNaN(real) || -3 > real || real > 3) { throw new Error("Bad real part") }
+		if (isNaN(imag) || -3 > imag || imag > 3) { throw new Error("Bad imaginary part") }
 		matrix_entries[i] = real;
 		matrix_entries[i+1] = imag;
 		p_draw()