Why to convert js the navigation bar to comments in the code above is not an error is displayed no t-CodePudding

CodePudding user response:

Because in the event you use events outside the loop variable I,
When the event is triggered, the cycle would have ended, at that time I value is the maximum cycle plus 1,
You can put the events in the lis [I] to this

Have to use a variable I, closures can be used to save lives the value of the current cycle I

 
For (I=0; i (function (I) {
The lis [I]. Style. onm ouseover=function () {
Uls=lis [I] getElementsByTagName (" ul "); 
Uls [0]. Style. Height="130 px" 
} 
Lis [I] style. The onm ouseout=function () {
Uls=lis [I] getElementsByTagName (" ul "); 
Uls [0]. Style. Height="0" 
} 
}) (I); 
}

CodePudding user response:

There are
The lis [I]. Style. onm ouseover
To change
The lis [I]. onm ouseover

CodePudding user response:

Window. The onl oad=function () {
Var lis=document. GetElementsByClassName (" li1 ");
Var uls=document. QuerySelectorAll (". Li1 ul ")
for(var i=0; i The lis [I] index=I;
The lis [I] onm ouseover=function () {
for(var j=0; J & lt; The lis. Length; J++) {
Uls [j] style. Height="0";
}
Uls [this index]. Style. Height="130 px";
}

The lis [I] onm ouseout=function () {
for(var j=0; J & lt; The lis. Length; J++) {
Uls [j] style. Height="0";
}

}

}
}
You try this