javascript - what do these lines of code mean -

function nxt() {     if( lights < imglen-1 ) {         lights++;     } else {         lights=0;                     }      imgelement.src = img[lights];                     } 

i have researched code still don't know means, can me explaining each line of code does/means thankyou can please explain means

when saw question, seems beginner. don't know know programming, should try study basics.

in other hand, have said understand. :p

  function nxt() // create new function. nxt mean "next" { // delimite start of function     if(lights < imglen-1) // if value of lights under value of imglen - 1          {             lights++; // add 1 value of lights         }     else{ // otherwise             lights=0;  // set value of lights 0                       }         imgelement.src = img[lights]; // finally, assign imgelement img adress img @ pos of value of lights                     }