js declaration can not get the value of the variable
iframe load a page, In loading the iframe page get iframe in the let declare global variable output undefined, example code as follows
click the button output
undefined
admin
<iframe src="2.html" id="i"></iframe>
<input type="button" onclick="alert(i.contentWindow.role+'\n'+i.contentWindow.role1)" value="输出iframe中变量" />
2.html
<script>
let role = "admin";
var role1 = "admin";
</script>
0 Answer
When you write an event to the input the iframe is not loaded yet so you can't get the value you should change it to something like this so that when you click on it it's loaded
<iframe src="2.html" id="i">iframe>
<input type="button" onclick="get()" value="输出iframe中变量" />
<script>
function get(){
alert(i.contentWindow.role1)
}
script>
let declared variable will not be attached to the window variable, if not, var will be attached to the window variable.
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