kiedis Posted December 31, 2012 Share Posted December 31, 2012 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 Link to comment Share on other sites More sharing options...
jeffman Posted December 31, 2012 Share Posted December 31, 2012 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. Link to comment Share on other sites More sharing options...
kiedis Posted December 31, 2012 Author Share Posted December 31, 2012 Great explanation, thank you very much! Link to comment Share on other sites More sharing options...
thescientist Posted January 22, 2013 Share Posted January 22, 2013 There's also an explanation of for loops in the tutorialshttp://www.w3schools.com/js/js_loop_for.asp Link to comment Share on other sites More sharing options...
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