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 var str = ''; if(str.length === 0){ document.write('String is empty'); } Following is the out...
if (!String.prototype.includes) { Object.defineProperty(String.prototype, 'includes', { value: function(substring, searchposition) { if (typeof searchposition!== 'number') { searchposition= 0 } if (searchposition+ substring.length > this.length) { return false } else { return this.i...
}//---长度是否对 by lyj ---function notLength(name, length, str) {if(trim(name.value).length !=length) { alert(str); name.focus();returntrue; }returnfalse; }//---固定长度的数字---function notLandN(name, length, str) {if(trim(name.value).length != length ||isNaN(trim(name...
function checkString(value){ return /^[\Α-\￥\w]+$/.test(value); } function checkTelLength(value){ if(value.length<7){ return false; } return true; } function changeStrNull(str){ if(typeof(str) == "undefined" || str == ""){ str = ""; } return str; } //非字母特殊符号...
function isCheck(arr) { for (let i = 0; i < arr.length; i++) { if (arr[i] === 0) { arr[i] = 'zero'; } else if (arr[i] % 2 === 0) { arr[i] = 'even'; } else { arr[i] = 'odd'; } } return arr; } 上述代码中,我们遍历了数组arr中的每个元素,并根据特...
String.includes() Method The String.includes()provides the most simple and popular way to check if a string contains a substring in modern JavaScript. It was introduced in ES6 and works in all modern browsers except Internet Explorer. The String.includes() method returns true if the string con...
this.methodOnly = true // also, ok, y's type is string | boolean | undefined } } 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 如果一个属性从没在类内设置过,它们会被当成未知的。 如果类的属性只是读取用的,那么就在构造函数里用JSDoc声明它的类型。 如果它稍后会被初始化...
check if the string contains spaces by passing a whitespace string to the method. Since the method returns an index when a whitespace exists, we can check if the value is greater than or equal to zero which returnstrueif there is a whitespace in any index of the string andfalseif ...
}varerrorArray = errorString.split('||');varruleArray =[];for(vari =0, j = validArray.length; i < j; i++){ ruleArray.push({ funTitle:validArray[i], errorMsg:errorArray[i] }); }returnself.validataResult(el,ruleArray);
Today, I probably lean more towardsString.includes(), with a polyfill. It’s rare that I actually need the index of the substring. I generally just want to know if it exists or not. If you don’t want to bother with the polyfill,String.indexOf()still gets the job done, though!