使用Java重置元标记

Question

I'm using these two functions to set and reset meta tags after I instigate an JS application

function setMeta(){
        alert("meta set");
        $('meta[name=viewport]').attr('content', 'width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no, user-scalable=0');
    }

function resetMeta(){
        alert("meta reset");
        $('meta[name=viewport]').attr('content', ' width=device-width, initial-scale=1.0,maximum-scale=1.6, user-scalable=yes, user-scalable=1');
}

My question: What is default value of the initial-scale propertie. If I don't reset it it stays 1.0 as it was set.

Update question: If the page where I open my JS app is scaled.The page doesn't get set to 1.0 scale as in setMeta function when I open the dialog. Where could the problem be? The other properties like user-scalable work fine...

Answer 1

The default value is 1.0 , see this page :

The viewport initial-scale parameter specifies the scale (zooming) of a web page the first time it is displayed. The default value of 1.0 specifies no scaling . Larger values up to 10 zoom in (enlarge) the page, and smaller values down to 0.1 zoom out (shrink) the page.

---

To set it to the value it was before, just store it.

function setMeta(){
        alert("meta set");
        oldcontent=$('meta[name=viewport]').attr('content') //store the current value
        $('meta[name=viewport]').attr('content', 'width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no, user-scalable=0');
}

function resetMeta(){
        alert("meta reset");
        $('meta[name=viewport]').attr('content', oldcontent);
}