Question

<HTML>
<HEAD>
<TITLE>counter </TITLE>
</head>
<body>


<script type="text/javascript">

var clicks = 0;
function linkClick(){
document.getElementById('clicked').value = ++clicks;
}
document.write('<a href="#" onclick="linkClick()">Add</a>');
</script>

<input id="clicked" size="3" onfocus="this.blur();" value="0" >
<script type="text/javascript">
function linkClick1(){
document.getElementById('clicked').value = --clicks;
}
document.write('<a href="#" onclick="linkClick1()">Subtract</a>');
</script>
</BODY>
</HTML>

这个加上和减去取决于它点击的次数我希望值不低于0怎么做??

Answer 1

替换：

document.getElementById('clicked').value = ++clicks;

在：

document.getElementById('clicked').value = clicks >= 0? --clicks : clicks;

如果没有添加注释，这可能会有效：）

Answer 2

function linkClick1(){
    if (clicks > 0) {
       document.getElementById('clicked').value = --clicks;
    }
}

Answer 3

这更实用：

function linkClick1(){
    if (clicks > 0) {
       document.getElementById('clicked').value = --clicks;
    }
}

Javascript点击计数器

3 个答案: