background.js

chrome.runtime.onMessage.addListener(
    function(data, sender, onSuccess) {
		if (data.type!=="url"){return};
		console.log("get");
		var url = data.url;
		if (data.cors==false){var mode ="no-cors"} else {var mode = "cors"};
        fetch(url, {method:"get", mode:mode})
            .then(response => response.text())
            .then(responseText => onSuccess(responseText))
        
        return true;  // Will respond asynchronously.
    }
);
chrome.runtime.onMessage.addListener(
    function(data, sender, onSuccess) {
		if (data.type!=="urlPost"){return};
		console.log("post");
		var url = data.url;
		if (data.formData!==undefined){
		var formData = new FormData();
		var pData=data.formData;
		for (i in pData){
			formData.append(i, pData[i]);
		};
		if (data.cors=false){
		console.log(formData);
        fetch(url, {method:"POST", body:formData, mode:"no-cors"})
            .then(response => response.text())
            .then(responseText => onSuccess(responseText))
        } else {
		console.log(formData);
        fetch(url, {method:"POST", body:formData})
            .then(response => response.text())
            .then(responseText => onSuccess(responseText))
		}
        return true;  // Will respond asynchronously.
		} else if (data.rawData!==undefined){
		var pData=data.rawData;
		if (data.cors=false){
        fetch(url, {method:"POST", body:new URLSearchParams(pData), mode:"no-cors"})
            .then(response => onSuccess(response))
        } else {
		fetch(url, {method:"POST", body:new URLSearchParams(pData)})
            .then(response => onSuccess(response))
		}
        return true;  // Will respond asynchronously.
		}
    }
);