js中window.event.keyCode！=8什么意思？

js中window.event.keyCode！=8什么意思？

如果文本域里的字数多于199个的时候，就只能按BackSpace 键，否则键盘输不进内容，就是到达了199个数字打不进去了，只能删除一些数字再打了！

判断事件按下的是否为 backspace 键 event.keycode值大全 1 keycode 8 = backspace backspace 2 keycode 9 = tab tab 3 keycode 12 = clear 4 keycode 13 = enter 5 keycode 16 = shift_l 6 keycode 17 = control_l 7 keycode 18 = alt_l 8 keycode 19 = pause 9 keycode 20 = caps_lock 10 keycode 27 = escape escape 11 keycode 32 = space space 12 keycode 33 = prior 13 keycode 34 = next 14 keycode 35 = end 15 keycode 36 = home 16 keycode 37 = left 17 keycode 38 = up 18 keycode 39 = right 19 keycode 40 = down 20 keycode 41 = select 21 keycode 42 = print 22 keycode 43 = execute 23 keycode 45 = insert 24 keycode 46 = delete 25 keycode 47 = help 26 keycode 48 = 0 equal braceright 27 keycode 49 = 1 exclam onesuperior 28 keycode 50 = 2 quotedbl twosuperior 29 keycode 51 = 3 section threesuperior 30 keycode 52 = 4 dollar 31 keycode 53 = 5 percent 32 keycode 54 = 6 ampersand 33 keycode 55 = 7 slash braceleft 34 keycode 56 = 8 parenleft bracketleft 35 keycode 57 = 9 parenright bracketright 36 keycode 65 = a a 37 keycode 66 = b b 38 keycode 67 = c c 39 keycode 68 = d d 40 keycode 69 = e e eurosign 41 keycode 70 = f f 42 43 keycode 71 = g g 44 keycode 72 = h h 45 keycode 73 = i i 46 keycode 74 = j j 47 keycode 75 = k k 48 keycode 76 = l l 49 keycode 77 = m m mu 50 keycode 78 = n n 51 keycode 79 = o o 52 keycode 80 = p p 53 keycode 81 = q q at 54 keycode 82 = r r 55 keycode 83 = s s 56 keycode 84 = t t 57 keycode 85 = u u 58 keycode 86 = v v 59 keycode 87 = w w 60 keycode 88 = x x 61 keycode 89 = y y 62 keycode 90 = z z 63 keycode 96 = kp_0 kp_0 64 keycode 97 = kp_1 kp_1 65 keycode 98 = kp_2 kp_2 66 keycode 99 = kp_3 kp_3 67 keycode 100 = kp_4 kp_4 68 keycode 101 = kp_5 kp_5 69 keycode 102 = kp_6 kp_6 70 keycode 103 = kp_7 kp_7 71 keycode 104 = kp_8 kp_8 72 keycode 105 = kp_9 kp_9 73 keycode 106 = kp_multiply kp_multiply 74 keycode 107 = kp_add kp_add 76 keycode 108 = kp_separator kp_separator 77 keycode 109 = kp_subtract kp_subtract 78 keycode 110 = kp_decimal kp_decimal 79 keycode 如果没按BackSpace 键

当你在 id="txt" 文本域中输入文字时，如果长度大于199.而且你接下的输入的不是退格键。那么文本域不接收你的输入。