function - onmouseover Event in For Loop JavaScript Supplies Incorrect Arguments -

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• javascript closure inside loops – simple practical example 31 answers

so, have loop , array. in each of elements in array buttons, want have onmouseover event.

note: code simplified make point.

for(i = 0; < array.length; i++){     var button = document.createelement("button");     button.onmouseover = function() {dosomething(i)}; } 

where dosomething accepts 1 parameter, i.

when cursor hover on of butttons, argument supplied dosomething - i, length of array, regardless of button cursor hovering over. why happen, , can ensure correct arguments supplied function?

you binding variable, not value. i.e. have created closure in functions utilize same variable i, not new variable value of i.

what need lock in value , 1 way can create function generator , invoke current value of i. e.g.

for(i = 0; < array.length; i++){     var button = document.createelement("button");     button.onmouseover = function(inner_i) { return function(){dosomething(inner_i)} }(i); }