Copy Code code as follows:
Console.log ('----1----')
Console.log (' 12 ' + ' 34 ')//' 1234 '
Console.log (' 12 ' + 34)//' 1234 '
Console.log (12 + ' 34 ')//' 1234 '
Console.log (12 + 34)//46
Console.log ('----2----')
Console.log (+ ' 12 ' + ' 34 ')//' 1234 '
Console.log (+ ' 12 ' + 34)//46
Console.log (+12 + ' 34 ')//' 1234 '
Console.log (+12 + 34)//46
Console.log ('----3----')
Console.log (-' 12 ' + ' 34 ')//'-1234 '
Console.log (-' 12 ' + 34)//22
Console.log (-12 + ' 34 ')//'-1234 '
Console.log (-12 + 34)//22
Console.log ('----4----')
Console.log (' 12 '-' 34 ')//-22
Console.log (' 12 '-34)//-22
Console.log (12-' 34 ')//-22
Console.log (12-34)//-22
Console.log ('----5----')
Console.log (+ ' 12 '-' 34 ')//-22
Console.log (+ ' 12 '-34)//-22
Console.log (+12-' 34 ')//-22
Console.log (+12-34)//-22
Console.log ('----6----')
Console.log (-' 12 '-' 34 ')//-22
Console.log (-' 12 '-34)//-22
Console.log (-12-' 34 ')//-22
Console.log (-12-34)//-22
Simultaneous number addition of string concatenation in JavaScript
document.write ("If I=1, the above code output is
If you want to output to 2.jpg, you should write this
document.write ("<img src= ' images/" + (i+1) + ". jpg ' >")