效果如图:
直接上源码:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 | <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> 123 <script> var check = (function () { var callbacks = [], timeLimit = 2, open = false; setInterval(loop, 2); return { addListener: function (fn) { callbacks.push(fn); }, cancleListenr: function (fn) { callbacks = callbacks.filter(function (v) { return v !== fn; }); } } function loop() { var startTime = new Date(); debugger; if (new Date() - startTime > timeLimit) { if (!open) { callbacks.forEach(function (fn) { fn.call(null); }); } open = true; } else { open = false; } } })(); check.addListener(function () { //alert('Open Devtool'); }); </script> </body> </html> |