function contains(string, substr, isIgnoreCase) { if (isIgnoreCase) { string = string.toLowerCase(); substr = substr.toLowerCase(); } var startChar = substr.substring(0, 1); var strLen = substr.length; for (var
To check if a Javascript String Contains a substring or not, we can use 7 different Javascript methods as listed in below table.
let str3 = 'JavaScript';if (str3.includes('Script')) { alert(`The string "${str3}" contains "Script".`);} else { alert(`The string "${str3}" does not contain "Script".`);} 五、注意事项 1、includes()方法区分大小写。2、如果搜索字符串为空，则返回true。3、如果指定的起始位置大...
if(!String.prototype.includes){String.prototype.includes=function(search,start){'use strict';if(typeofstart!=='number'){start=0;}if(start+search.length>this.length){returnfalse;}else{returnthis.indexOf(search,start)!==-1;}};} 规范 ...
How do you check if one string contains a substring in JavaScript?Craig Buckler
但是,如果变量number在if块外已经声明,将会出现下面的结果。 代码语言:javascript 代码运行次数:0 运行 AI代码解释 // ES6 CodeletisValid=true;letnumber=20;if(isValid){letnumber=10;console.log('inside:',number);// inside: 10}console.log('outside:',number);// outside: 20 ...
1if(largeString.indexOf(shortString) != -1)2{3//如果包含,进行相应处理;4} 也许一个字符串会包含另一字符串不止一次,这时第二个参数startIndex也许会派上用场,下面这个函数演示如何求得一个字符串包含另外一个字符串的次数: 1functioncountInstances(mainStr, subStr)2{3varcount = 0;4varoffset = 0;...
console.log(containsProfanity(message)); // true 3. 路径处理:在URL、文件路径或目录结构中,检查是否包含特定路径片段、文件扩展名等。 function isImageFile(path) { return path.endsWith(".jpg") || path.endsWith(".png") || path.includes(".jpeg"); ...
if (window.foo) { doSomething(); } 但是,有的情况下,我们有更深的结构和需要更合适的检查的时候,可以这样: // UGLY: we have to proof existence of every // object before we can be sure property actually exists if (window.oFoo && oFoo.oBar && oFoo.oBar.baz) { ...
If you omit the second parameter, the method will slice out the rest of the string: lettext ="Apple, Banana, Kiwi"; letpart = text.slice(7); Try it Yourself » If a parameter is negative, the position is counted from the end of the string: ...