javascript - Changing an array value also changes value in another assigned array -

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i learning javascript , in w3 schools' code editor try following code :

    <!doctype html> <html> <body>  <p id="demo"></p>  <script> var cars = ["saab", "volvo", "bmw"]; var newcars = []; newcars = cars; newcars[0] = "benz" document.getelementbyid("demo").innerhtml = cars[0]; </script>  </body> </html>

i expected value : "saab" since made no changes cars array , change newcars array, yet output : "benz".

could please explain happening?

thanks

the value of variable "cars" contains "reference array" not "the array value". so, when go "var newcars = cars" copying reference only, means "cars" , "newcars" pointing same array. need make copy of array "cars" points , let "newcars" reference new copy. can clone array in different ways, done using libraries jquery (like here), underscore (like here) or without in here copying array value in javascript


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