如何使用if语句正确（javascript）

Question

I got this code that works perfectly fine, just like i want it to, but then i want to extend it with else if, but the way i have done my code, that's not possible. Feel free to link some good site to learn from.

if(wallLeft < marioLeft && wallLeftWidth > marioLeft)
{    

}
else
{
    newLeft = marioLeft - 5;
    mario.style.left = newLeft + "px";
}

//else if(wallLeftWidth < marioLeft && wallLeftWidth > marioLeftWidth)
{   }
else
{ //some code }

Answer 1

Inverse your conditions, writing if(...){}else{...} looks horrible and is really bad practice. Additionally the order is if , else if , else , you cant use else if after else .

if( wallLeft > marioLeft || wallLeftWidth < marioLeft ) {
    newLeft = marioLeft - 5;
    mario.style.left = newLeft + "px";
} else if( wallLeftWidth > marioLeft || wallLeftWidth < marioLeftWidth) {
    //some code 
}

Answer 2

Your code is wrong. Try this;

if (wallLeft < marioLeft && wallLeftWidth > marioLeft) {
    newLeft = marioLeft - 5;
    mario.style.left = newLeft + "px";
} else if (wallLeftWidth < marioLeft && wallLeftWidth > marioLeftWidth) { 
    //some code 
}