- JavaScript 運算符
- JavaScript 條件語句
- JavaScript 循環(huán)語句
- JavaScript 跳轉(zhuǎn)語句
運算符
運算符.png
//任何類型與字符串相加都會默認(rèn)轉(zhuǎn)為字符串類型
<p> i = 10 ,j = 10 ,i+ j = ?</p>
<p id="sumid"></p>
<button onclick="mysum()">結(jié)果</button>
<script>
function mysum() {
var i = 5;
var j = ".3d";
document.getElementById("sumid").innerHTML =i+j;
}
var i = 11;
document.write(i>10?"i大于10":"i小于10");
條件語句
if ...else
switch
<script>
var i = 5;
switch (i){
case 1:
document.write("i=1");
break;
case 2:
document.write("i=2");
break;
default:
document.write("條件不滿足case")
break;
}
</script>
循環(huán)語句
1.for 循環(huán)、for/in
2.while循環(huán)、do...while
var i =[1,2,3,4,5,6,7];
for(var j = 0 ;j<i.length ; j++){
document.write(i[j]+"、");
}
for(var j in i){
document.write(i[j]);
}
<script>
var i = 10;
while (i< 10){
document.write("i="+i+"<br/>");
i++;
}
do{ do while先執(zhí)行，后判斷，一般用while即可
document.write("i="+i+"<br/>");
i++;
}
while (i< 10)
</script>
JavaScript跳轉(zhuǎn)語句
1.break 跳出循環(huán)
2.continue 跳出本次循環(huán)，進(jìn)行下次循環(huán)
