if(string_name.length === 0){ // string is empty } ExampleBelow is the example code given, that shows how to use the length property to check the empty string.Open Compiler <html> <body> <script> var str = ''; i
Javascript check if string is empty 1 2 const string = ' '; 3 4 function isEmpty(str) { 5 return !str || str.trim().length === 0; 6 } 7 8 function checkString() { 9 var result = isEmpty(string); 10 if (result) { 11 document.getElementById("output").innerHTM...
functiongoodEmptyCheck(value){Object.keys(value).length===0&&value.constructor===Object;// 👈 constructor check}goodEmptyCheck(newString());// false ✅goodEmptyCheck(newNumber());// false ✅goodEmptyCheck(newBoolean());// false ✅goodEmptyCheck(newArray());// false ✅goodEmptyChec...
function check(value) { if ('string' == typeof value) { kongge1(value); kongge2(value); } else { console.log(typeof value); console.log('请输入字符串'); } } /* 使用String.trim()函数,来判断字符串是否全为空*/ function kongge1(test) { let str = test.trim(); if (str.leng...
If you want to check whether the string is empty/null/undefined, use the following code:let emptyStr; if (!emptyStr) { // String is empty }If the string is empty/null/undefined if condition can return false: Javascript empty string...
log(check(s)); Output typeof vs instanceof: Feature typeof instanceof Purpose Checks the type of a value Checks if an object is an instance of a class/constructor String Literal "string" false String Object "object" trueMayank Agarwal Updated on:...
TheJSON.stringifymethod is used to convert a JavaScript object to a JSON string. So we can use it to convert an object to a string, and we can compare the result with{}to check if the given object is empty. Let’s go through the following example. ...
Checking this is easy. We just need to use thetrimmethod.trimremoves any whitespace from the front and back of a string. constvalue=input.value.trim() If the input is valid, you can setdata-statetovalid. If the input is invalid, you can set thedata-statetoinvalid. ...
The best way to check if an array is empty in JavaScript is by using the Array.isArray() method (ES5+) and array's length property together like so: // ES5+ if (!Array.isArray(array) || !array.length) { /
deleteCharAt(len - 1); } if (StringUtils.isNotBlank(bf.toString())) { return "包含手机号"; } else { return "ok"; } } /*** * 描述: 包含固定电话 * * @param content 电话 * @return String */ public static String checkPhone(String content) { List<String> list = new ArrayList<>...