diff --git a/js/js.libraries/src/core/core.kt b/js/js.libraries/src/core/core.kt
index bab10fde7f9..d036b27b6e3 100644
--- a/js/js.libraries/src/core/core.kt
+++ b/js/js.libraries/src/core/core.kt
@@ -7,9 +7,10 @@ public external fun eval(expr: String): dynamic = noImpl
 
 public external val undefined: Nothing? = noImpl
 
-
+@Deprecated("Use toInt(radix) instead.", ReplaceWith("s.toInt(radix)"), level = DeprecationLevel.ERROR)
 public external fun parseInt(s: String, radix: Int = noImpl): Int
 
+@Deprecated("Use toDouble() instead.", ReplaceWith("s.toDouble()"), level = DeprecationLevel.ERROR)
 public external fun parseFloat(s: String, radix: Int = noImpl): Double
 
 public external fun js(code: String): dynamic = noImpl
diff --git a/js/js.translator/testData/box/inlineMultiFile/tryCatch.kt b/js/js.translator/testData/box/inlineMultiFile/tryCatch.kt
index 82e91a9ae46..15d2f4c97a1 100644
--- a/js/js.translator/testData/box/inlineMultiFile/tryCatch.kt
+++ b/js/js.translator/testData/box/inlineMultiFile/tryCatch.kt
@@ -69,6 +69,6 @@ inline fun <T, R> T.perform(job: (T)-> R) : R {
     return job(this)
 }
 
-inline fun String.toInt2() : Int = parseInt(this)
+inline fun String.toInt2() : Int = this.toInt()
 
 class RuntimeExceptionWithValue(val value: String) : RuntimeException()
\ No newline at end of file
diff --git a/js/js.translator/testData/box/inlineMultiFile/tryCatch2.kt b/js/js.translator/testData/box/inlineMultiFile/tryCatch2.kt
index 78c74fbfda3..7b639319a67 100644
--- a/js/js.translator/testData/box/inlineMultiFile/tryCatch2.kt
+++ b/js/js.translator/testData/box/inlineMultiFile/tryCatch2.kt
@@ -140,6 +140,6 @@ external object Number {
     fun parseInt(str: String): Int = noImpl
 }
 
-inline fun String.toInt2(): Int = parseInt(this)
+inline fun String.toInt2(): Int = this.toInt()
 
 class RuntimeExceptionWithValue(val value: String = "") : RuntimeException()
\ No newline at end of file
diff --git a/js/js.translator/testData/box/inlineMultiFile/tryCatchFinally.kt b/js/js.translator/testData/box/inlineMultiFile/tryCatchFinally.kt
index cf85138dabb..af9df636218 100644
--- a/js/js.translator/testData/box/inlineMultiFile/tryCatchFinally.kt
+++ b/js/js.translator/testData/box/inlineMultiFile/tryCatchFinally.kt
@@ -104,4 +104,4 @@ inline fun <T, R> T.performWithFailFinally(job: (T)-> R, failJob : (e: RuntimeEx
     }
 }
 
-inline fun String.toInt2() : Int = parseInt(this)
\ No newline at end of file
+inline fun String.toInt2() : Int = this.toInt()
\ No newline at end of file
diff --git a/js/js.translator/testData/webDemoExamples1/cases/ifAsExpression.kt b/js/js.translator/testData/webDemoExamples1/cases/ifAsExpression.kt
index bfe971a9f75..2656e0986c9 100644
--- a/js/js.translator/testData/webDemoExamples1/cases/ifAsExpression.kt
+++ b/js/js.translator/testData/webDemoExamples1/cases/ifAsExpression.kt
@@ -1,5 +1,3 @@
 fun main(args: Array<String>) {
-    println(max(parseInt(args[0]), parseInt(args[1])))
+    println(maxOf(args[0].toInt(), args[1].toInt()))
 }
-
-fun max(a: Int, b: Int) = if (a > b) a else b
\ No newline at end of file
diff --git a/js/js.translator/testData/webDemoExamples1/cases/nullChecks.kt b/js/js.translator/testData/webDemoExamples1/cases/nullChecks.kt
index af61d76fc08..658d3d93fa2 100644
--- a/js/js.translator/testData/webDemoExamples1/cases/nullChecks.kt
+++ b/js/js.translator/testData/webDemoExamples1/cases/nullChecks.kt
@@ -1,12 +1,6 @@
 // Return null if str does not hold a number
-fun myParseInt(str: String): Int? {
-    try {
-        return parseInt(str)
-    }
-    catch (e: NumberFormatException) {
-        println("One of argument isn't Int")
-    }
-    return null
+fun myParseInt(str: String): Int? = str.toIntOrNull().also {
+    if (it == null) println("One of arguments isn't Int")
 }
 
 fun main(args: Array<String>) {
diff --git a/js/js.translator/testData/webDemoExamples1/cases/ranges.kt b/js/js.translator/testData/webDemoExamples1/cases/ranges.kt
index 2355da22443..cc5bfefed08 100644
--- a/js/js.translator/testData/webDemoExamples1/cases/ranges.kt
+++ b/js/js.translator/testData/webDemoExamples1/cases/ranges.kt
@@ -1,6 +1,6 @@
 
 fun main(args: Array<String>) {
-    val x = parseInt(args[0])
+    val x = args[0].toInt()
     //Check if a number lies within a range:
     val y = 10
     if (x in 1..y - 1)
diff --git a/js/js.translator/testData/webDemoExamples2/cases/bottles.kt b/js/js.translator/testData/webDemoExamples2/cases/bottles.kt
index 4ea5c7fd74f..1b41b065048 100644
--- a/js/js.translator/testData/webDemoExamples2/cases/bottles.kt
+++ b/js/js.translator/testData/webDemoExamples2/cases/bottles.kt
@@ -32,7 +32,7 @@ fun main(args: Array<String>) {
         printBottles(99)
     }
     else {
-        val bottles = parseInt(args[0]);
+        val bottles = args[0].toIntOrNull()
         if (bottles != null) {
             printBottles(bottles);
         }