解读JavaScript中For,While与递归的用法_基础知识

代码如下:

for(i=start; i

}

代码如下:

while (condition) {
//do something;
//change condition;
}

代码如下:

function substring(all, start, end) {
for(i=start; i<=end; i++) {
console.log(all[i]);
}

substring("eclipse", 1, 4); //clip

代码如下:

function substring(all, start, end) {
if(start >= end) {
return all[start];
}
else {
return all[start] + substring(all, start+1, end);
}

substring("eclipse", 1, 4); //clip

对于数组,字符串, 我们使用index []访问特定的值; 对于对象,也是一样使用[], 但我们会使用一个特殊的变量: propertyName

代码如下:

var person = {
name: "Morgan Jones",
telephone: "(650) 777 - 7777",
email: "morgan.jones@example.com"
};

for (var propertyName in person) {
console.log(propertyName + ":"+ person[propertyName]);
}

代码如下:

var table = [
["Person", "Age", "City"],
["Sue", 22, "San Francisco"],
["Joe", 45, "Halifax"]
];

var i;
var rows=table.length;
for (r=0;r var c;
var cells = table[r].length;
var rowText = "";
for (c=0;c rowText += table[r][c];
if (c rowText += " ";
}
}
console.log(rowText);
}

Sue 22 San Francisco

Joe 45 Halifax

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break:

使用break立刻退出循环, 适用于for和while循环.