4.表单提交(空格提交的问题)例 4.1(form.submitIEFF.html) function check() { var form = document.getElementById("regForm"); if (form.user.value == "") { alert("用户名不能为空!"); } else { form.submit(); } } 用户 <INPUT TYPE="button" onclick="check();" id="regBut"...
备注说明,对象中的成员,可以直接用来访问,不用事先判断是否存在(但是对象要先存在) 摘自: http://stackoverflow.com/questions/5515310/is-there-a-standard-function-to-check-for-null-undefined-or-blank-variables-in https://www.quora.com/What-is-the-best-way-to-check-if-a-property-or-variable-is-...
tuesday:{location:location??"Park",budget:budget??200},};}else{newPlans??=plans;//will only override if newPlans is undefinedconsole.log("Plans have already been added!");}returnnewPlans;}varnewPlans=addPlansWhenUndefined(travelPlans,"Ford Theatre",null);console.log...
context) { var result;return function() { if(fn) {result = fn.apply(context || this, arguments);fn = null;}return result;};}// Usagevar canOnlyFireOnce = once(function() {console.log('Fired!'
Previous to v3.0.0, .only() used string matching to decide which tests to execute; this is no longer the case. In v3.0.0 or newer, .only() can be used multiple times to define a subset of tests to run: describe('Array', function() { describe('#indexOf()', function() { it....
/*! jQuery FineUI v3.5.0.1 | http://fineui.com/ */ (function () { var n = !1, t = /xyz/.test(function () { xyz }) ? /\b_super\b/ : /.*/; this.Class =
jsClass; private string? result; protected override void OnInitialized() => jsClass = new(JS); private async Task SetStock() { if (jsClass is not null) { stockSymbol = $"{(char)('A' + Random.Shared.Next(0, 26))}" + $"{(char)('A' + Random.Shared.Next(0, 26))}";...
转换为string拼接空字符串 转换为布尔使用Boolean();注意:0、空字符串、undefined、null 、NaN会被转换为逻辑假false,其他类型在转化为布尔时,转换为true <!DOCTYPE html> Title /* 数据类型 */ // var name = 'tom'; // var age = 18; // var height = 180.5; // // var flag = true; ...
upcase # Don't save product and return from method if there is already saved item with the same sku: return unless unique?(:sku, item[:sku]) # ... save_to "results.json", item, format: :json end end unique? helper works pretty simple: # Check string "http://example.com" in ...
3.7 Do not call Object.prototype methods directly, such as hasOwnProperty, propertyIsEnumerable, and isPrototypeOf. eslint: no-prototype-builtins Why? These methods may be shadowed by properties on the object in question - consider { hasOwnProperty: false } - or, the object may be a null ...