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explanation needed regarding JavaScript Array Object


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hi. learnign JavaScript from tutorial provided at http://www.w3schools.com/js/default.asp In JavaScript Array Object section, I was presented with this script: <script>var i;var mycars = new Array();mycars[0] = "Saab";mycars[1] = "Volvo";mycars[2] = "BMW";for (i=0;i<mycars.length;i++){document.write(mycars + "<br>");}</script> I realize that this code says to increase integer value by 1 as long as i<mycars.length But i don't get what is mycars.length in this case? The length of "mycars" (6 characters in this case?) I experimented by adding additional variables: <script>var i;var mycars = new Array();mycars[0] = "Saab";mycars[1] = "Volvo";mycars[2] = "BMW";mycars[3] = "boeing";mycars[4] = "volga";mycars[5] = "airbus";mycars[6] = "tupolev";mycars[7] = "yak";for (i=0;i<mycars.length;i++){document.write(mycars + "<br>");}</script> and i hoped that this addition of new variables will disrupt this function but no, all new variables were displayed properly when i clicked "submit code". Then i changed the function in this place:for (i=0;i=mycars.length;i++) and then immediately my internet browser froze and i had to close it down. So, what kind of length does the mycars.length indicate here and why it's so important that i< mycars.length here? just can't get it :D

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mycars.lengthis the number of elements in the array object. The goal of the loop is to cycle through all the elements. So it starts with mycars[0] and loops until it reaches the element before mycars[mycars.length]. i=mycars.length uses the assignment operator ( = ), not the test-for-eqality operator ( == ) so the value never changes. i always = mycars.length so the loop never ends. That's why you crashed.

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  • 4 weeks later...

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