Analysis of javascript switch usage precautions_javascript skills

This article analyzes the usage notes of switch in javascript with examples. Share it with everyone for your reference. The specific analysis is as follows:

Let’s look at the following code first:

<script>
var t_jb51_net = 65;
switch (t_jb51_net) {
case '65':
alert("字符串65。jb51.net");
break;
}
</script>

You will find that no dialog box pops up and the alert is not executed.

Cause analysis:

What needs to be made clear here is that switch uses the congruent sign "===" when making judgments. When comparing congruent signs, it first checks whether the data types are the same, and here, t_jb51_net is of Number type. , and '65' is String.

The following code will pop up the dialog box:

<script>
var t_jb51_net = 65;
switch (t_jb51_net) {
case 65:
alert("数字65。jb51.net");
break;
}
</script>

I hope this article will be helpful to everyone’s JavaScript programming design.