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POJava applet not visible in Chrome
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copied!<p>I'm running into some kind race condition in a Java applet, peculiar to Google Chrome (win xp). I'm writing the <code><applet></code> tag into a popup window.</p> <p>The problem is characterised by: </p> <ol> <li>The applet <strong>always shows fine in MS IE and Firefox</strong>.</li> <li>In Chrome The applet only displays about <strong>50%</strong> of the time.</li> <li>When it doesn't display, the applet actually appears to be silently running perfectly from the Java console! No errors!</li> <li>The <code>JApplet</code>'s <code>init()</code> and <code>start()</code> methods are always called.</li> <li><code>isShowing()</code> and <code>isDisplayable()</code> always return <code>true</code>, even when the applet does not show.</li> <li>When it doesn't show, the <code>paint()</code> method <strong>isn't</strong> called.</li> <li>When the applet doesn't show, a transparent rectangular area (of the window background colour) where the applet should have been can be noticed when the text in the window is selected. From this I take it that the applet region is correctly placed in the window.</li> </ol> <h2>My code:</h2> <p>MyApplet.java</p> <pre><code> package mypackage; public class MyApplet extends JApplet { public void init(){ super.init(); getContentPane().add(new JLabel("Hello"), BorderLayout.CENTER); System.out.println("init ok"); } public void start() { super.start(); System.out.println("s parent:"+this.getParent()); System.out.println("s disp:"+this.isDisplayable()); System.out.println("s showing:"+this.isShowing()); } public void paint(Graphics g){ System.out.println("painting"); super.paint(g); } } </code></pre> <p>test.html</p> <pre><code><HTML> <SCRIPT language='JavaScript'> var jarpath='./myjar.jar'; var classname='mypackage.MyApplet'; function opentest(){ applet=window.open('', '', "height=420,width=620"); applet.document.write( '<html><body>'+ '<OBJECT classid="clsid:8AD9C840-044E-11D1-B3E9-00805F499D93"'+ 'width=600 height=400>'+ '<param name=code value="'+classname+'">'+ '<param name=archive value="'+jarpath+'">'+ '<param name=type value="application/x-java-applet;version1.3">'+ '<COMMENT>'+ '<EMBED code="'+classname+'" archive="'+jarpath+'" ' + 'type="application/x-java-applet;version=1.3" ' + 'width=600 height=400 ' + '>'+ '<NOEMBED>' + 'unavailable'+ '</NOEMBED>'+ '</EMBED>' + '</COMMENT>' + '</OBJECT>'+ '</body></html>' ); } </SCRIPT> <BODY> Click here to open <A onclick="opentest()">Test</A> </BODY> </HTML> </code></pre> <h2>Output from console</h2> <p>50% of the time I click on 'Test', the new window contains the 'Hello' label. The other 50% of the time, the window is blank as described. The console output seems identical when the applet loads and doesn't load. It seems blameless!</p> <pre><code>security: property package.access value sun.,com.sun.xml.internal.ws.,com.sun.xml.internal.bind.,com.sun.imageio. security: property package.access new value sun.,com.sun.xml.internal.ws.,com.sun.xml.internal.bind.,com.sun.imageio.,com.sun.javaws security: property package.access value sun.,com.sun.xml.internal.ws.,com.sun.xml.internal.bind.,com.sun.imageio.,com.sun.javaws security: property package.access new value sun.,com.sun.xml.internal.ws.,com.sun.xml.internal.bind.,com.sun.imageio.,com.sun.javaws,com.sun.deploy security: property package.access value sun.,com.sun.xml.internal.ws.,com.sun.xml.internal.bind.,com.sun.imageio.,com.sun.javaws,com.sun.deploy security: property package.access new value sun.,com.sun.xml.internal.ws.,com.sun.xml.internal.bind.,com.sun.imageio.,com.sun.javaws,com.sun.deploy,com.sun.jnlp security: property package.definition value null security: property package.definition new value com.sun.javaws security: property package.definition value com.sun.javaws security: property package.definition new value com.sun.javaws,com.sun.deploy security: property package.definition value com.sun.javaws,com.sun.deploy security: property package.definition new value com.sun.javaws,com.sun.deploy,com.sun.jnlp security: property package.access value sun.,com.sun.xml.internal.ws.,com.sun.xml.internal.bind.,com.sun.imageio.,com.sun.javaws,com.sun.deploy,com.sun.jnlp security: property package.access new value sun.,com.sun.xml.internal.ws.,com.sun.xml.internal.bind.,com.sun.imageio.,com.sun.javaws,com.sun.deploy,com.sun.jnlp,org.mozilla.jss security: property package.definition value com.sun.javaws,com.sun.deploy,com.sun.jnlp security: property package.definition new value com.sun.javaws,com.sun.deploy,com.sun.jnlp,org.mozilla.jss basic: Added progress listener: sun.plugin.util.GrayBoxPainter$GrayBoxProgressListener@137c60d basic: Plugin2ClassLoader.addURL parent called for file:/E:/Java/eclipse/MyApplet/myjar.jar network: Cache entry not found [url: file:/E:/Java/eclipse/MyApplet/myjar.jar, version: null] network: Cache entry not found [url: file:/E:/Java/eclipse/MyApplet/myjar.jar, version: null] basic: Applet loaded. basic: Applet resized and added to parent container basic: PERF: AppletExecutionRunnable - applet.init() BEGIN ; jvmLaunch dt 145396 us, pluginInit dt 331540 us, TotalTime: 476936 us init ok basic: Applet initialized basic: Removed progress listener: sun.plugin.util.GrayBoxPainter$GrayBoxProgressListener@137c60d basic: Applet made visible basic: Starting applet basic: completed perf rollup s parent:sun.plugin2.main.client.PluginEmbeddedFrame[frame0,0,0,600x400,invalid,layout=java.awt.BorderLayout,title=,resizable,normal] s disp:true s showing:true basic: Applet started basic: Told clients applet is started </code></pre> <h2>Update</h2> <p>Thanks to Ates, trying the following timeout makes the Applet appear correctly <strong>100% of the time</strong>.</p> <pre><code>function opentest(){ applet=window.open('', '', "height=420,width=620"); setTimeout(function () { applet.document.write( ... ); } , 1000 ); } </code></pre> <ul> <li>As Ates mentions, we now see that our popup window doesn't like immediate <code>document.write</code>s!</li> <li>Is this correct behaviour? Am I supposed to wait for some signal before writing to a document?</li> <li>Should I be going about this a different way? Can I add some kind of listener to know when it is safe to call <code>document.write()</code>?</li> </ul>

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