For loop example: 1 2 3 4 5 6 var sum = 0; for (var i=1; i<=100; i++) { sum += i; } alert(sum); //5050 You may use break to jump out of the loop:1 2 3 4 5 6 7 var sum = 0; for (var i=1; i<=100; i++) { if (i == 50) break; stop the loop...
for...in loop and prototypesObjects in JavaScript can have properties inherited from object prototypes.For example, objects created using Array and Object constructors inherit many properties from Object.prototype and String.prototype. The for...in statement iterates over own properties of the object...
Example Let's look at an example that shows how to use a for-in loop in JavaScript. For example: var totn_colors = { primary: 'blue', secondary: 'gray', tertiary: 'white' }; for (var color in totn_colors) { console.log(totn_colors[color]); } In this example, the following...
JavaScript 支持不同类型的循环:for - 循环代码块一定的次数 for/in - 循环遍历对象的属性 while - 当指定的条件为 true 时循环指定的代码块 do/while - 同样当指定的条件为 true 时循环指定的代码块For 循环for 循环是您在希望创建循环时常会用到的工具。 下面是 for 循环的语法:...
This loop calculates the offset position of a node in the final-expression section, therefore making the use of a statement block useless, so the empty statement is used instead. Download the source code This was an example offorloops in JavaScript. ...
see something that we did not explain: the expressionbreak;. That expression is used to jump out of the loop, which means that it takes the command right after the loop, without executing the rest of it, but instead doing whatever code is next. Here’s an example of how you can use ...
<!-- var aProperty; document.write("Navigator Object Properties "); for (aProperty in navigator) { document.write(aProperty); document.write(""); } document.write ("Exiting from the loop!"); //--> Set the variable to different object and...
You can loop over a string with the JavaScript for...in loop. However, it’s not recommended to do so, as you’ll be looping over the indices of the characters rather than the characters themselves. A for…in loop string example In the example below, we’re looping over the following...
From the example above, you can read:Statement 1 sets a variable before the loop starts (var i = 0).Statement 2 defines the condition for the loop to run (i must be less than 5).Statement 3 increases a value (i++) each time the code block in the loop has been executed....
javascript中forin循环 js for in循环用法 分类 普通for循环 自行指定循环次数。 for (i = 0; i < loopTimes; i++) { console.log(i); } 1. 2. 3. 1 for..in循环 属历史遗留,用于遍历对象的属性(数组的索引值也算属性)。 但有一个缺点:如果手动向数组添加成员属性,则:...